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dancing links code 4-5

四、hdu 3663
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#include<stdio.h>
#include<algorithm>
#include<math.h>
#include<string.h>

using namespace std;

int n,m,DD,a[66][66],s[66],f[66],id[66][6];

const int MAXN = 1005;

int L[MAXN*MAXN], R[MAXN*MAXN], U[MAXN*MAXN], D[MAXN*MAXN];
int S[MAXN];
int Col[MAXN*MAXN], Row[MAXN*MAXN],Ans[MAXN],ans,limit,up;


void Remove(int c) {
	L[R[c]] = L[c];
	R[L[c]] = R[c];
	for (int i = D[c]; i != c; i = D[i])
	for (int j = R[i]; j != i; j = R[j]) {
	    U[D[j]] = U[j];
	    D[U[j]] = D[j];
	    -- S[Col[j]];
	}
}
void Resume(int c) {
	for (int i = U[c]; i != c; i = U[i])
	for (int j = L[i]; j != i; j = L[j]) {
	    U[D[j]] = j;
	    D[U[j]] = j;
	    ++ S[Col[j]];
	}
	L[R[c]] = c;
	R[L[c]] = c;
}

bool dfs(int depth) {
//    printf("ddd = %d  R0 = %d\n",depth,R[0]);
	if(R[0] == 0) { if(depth > ans)ans = depth; return true; }
	int i, j, c, minnum = 1000000000;
	for (i = R[0]; i != 0; i = R[i]) {
	    if (S[i] < minnum) {
	        minnum = S[i];
	        c = i;
	    }
	}
	Remove(c);
	for (i = U[c]; i != c; i = U[i]) {
	    Ans[depth] = Row[i];
	    for (j = R[i]; j != i; j = R[j]) Remove(Col[j]);
	    if (dfs(depth + 1)) return true;
	    for (j = L[i]; j != i; j = L[j]) Resume(Col[j]);
	}
	Resume(c);
	return false;
}
int solve(int n, int m, int DL[][MAXN]) {
	for (int i = 0; i <= m; i ++) {
	    L[i] = i - 1;
	    R[i] = i + 1;
	    U[i] = D[i] = i;
	}
	L[0] = m;
	R[m] = 0;
	int cnt = m + 1;
	memset(S, 0, sizeof (S));
	for (int i = 1; i <= n; i ++) {
	    int head = cnt, tail = cnt;
	    for (int c = 1; c <= m; c ++) if (DL[i][c]) {
	        S[c] ++;
	        Row[cnt] = i;
	        Col[cnt] = c;
	        U[D[c]] = cnt;
	        D[cnt] = D[c];
	        U[cnt] = c;
	        D[c] = cnt;
	        L[cnt] = tail;
	        R[tail] = cnt;
	        R[cnt] = head;
	        L[head] = cnt;
	        tail = cnt;
	        cnt ++;
	    }
	}
	if (dfs(0)) return true;
	return false;
}


int mark[MAXN][MAXN],x[MAXN],y[MAXN],z[MAXN];

int main()
{
	int i,j,k,l,row,col,g;
	while(scanf("%d %d %d",&n,&m,&DD) != EOF)
	{
	    for(i=1;i<=n;i++)
	        for(j=1;j<=n;j++)
	        {
	            a[i][j] = 0;
	            if(i == j)a[i][j] = 1;
	        }
	    while(m--) {
	        scanf("%d %d",&j,&k);
	        a[j][k] = a[k][j] = 1;
	    }
	    for(i=1;i<=n;i++)scanf("%d %d",&s[i],&f[i]);
	   
	    col = 0;
	    for(i=1;i<=n;i++)
	        for(j=1;j<=DD;j++)
	            id[i][j] = ++col;
	   
	    row = 0;
	    for(i=1;i<=n;i++)
	    {
	        for(j=s[i];j<=f[i];j++)
	            for(k=j;k<=f[i];k++)
	            {
	                row++; x[row] = j; y[row] = k; z[row] = i;
	                for(l=1;l<=col;l++)mark[row][l] = 0;
	               
	                for(l=1;l<=n;l++)if(a[i][l] == 1)
	                {
	                    for(g=j;g<=k;g++) mark[row][id[l][g]] = 1;
	                }
	            }
	    }
	   
	    int rr=0;
	   
	    for(i=1;i<=n;i++)
	    {
	        col++;
	        for(j=1;j<=row;j++)mark[j][col] = 0;
	       
	        for(j=s[i];j<=f[i];j++)
	            for(k=j;k<=f[i];k++)
	            {
	                rr++;
	                mark[rr][col] = 1;
	            }
	    }
	   
	    int TT = row;
	    for(i=1;i<=n;i++)
	    {
	        row++;
	        for(j=1;j<=col;j++)mark[row][j] = 0;
	        mark[row][col-n+i] = 1;
	    }
	   
	    ans = 0;
	   
	    k = solve(row, col, mark);
	   
	    if(k == 0)
	        printf("No solution\n");
	    else
	    {
	        for(i=1;i<=n;i++)s[i] = f[i] = 0;
	        for(i=0;i<ans;i++)
	        if(Ans[i] <= TT)
	        {
	            s[z[Ans[i]]] = x[Ans[i]];
	            f[z[Ans[i]]] = y[Ans[i]];
	        }
	        for(i=1;i<=n;i++)printf("%d %d\n",s[i],f[i]);
	    }
	    printf("\n");
	}
	return 0;
}
五、hdu 2995
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#include<stdio.h>
#include<algorithm>
#include<math.h>
#include<string.h>

using namespace std;

const int MAXN = 225;
int L[MAXN*MAXN], R[MAXN*MAXN], U[MAXN*MAXN], D[MAXN*MAXN];
int S[MAXN];
int Col[MAXN*MAXN];
int limit;

void Remove(int x) {
	for (int i = D[x]; i != x; i = D[i]) {
		L[R[i]] = L[i];
		R[L[i]] = R[i];
	}
}
void Resume(int x) {
	for (int i = U[x]; i != x; i = U[i]) {
		L[R[i]] = R[L[i]] = i;
	}
}
int Hash() {
	int ans = 0;
	bool hash[MAXN] = {0};
	for (int c = R[0]; c != 0; c = R[c])
	if (! hash[c]) {
		hash[c] = true;
		ans ++;
		for (int i = D[c]; i != c; i = D[i])
			for (int j = R[i]; j != i; j = R[j])
				hash[Col[j]] = true;
	}
	return ans;
}

bool dfs(int depth) {
	if (depth + Hash() > limit) return false;
	if (R[0] == 0) return true;
	int i, j, c, minnum = 2000000000;
	for (i = R[0]; i != 0; i = R[i]) {
		if (S[i] < minnum) {
			minnum = S[i];
			c = i;
		}
	}
	for (i = U[c]; i != c; i = U[i]) {
		Remove(i);
		for (j = R[i]; j != i; j = R[j]) Remove(j);
		if (dfs(depth + 1)) {
			for (j = L[i]; j != i; j = L[j]) Resume(j);
			Resume(i);
			return true;
		}
		for (j = L[i]; j != i; j = L[j]) Resume(j);
		Resume(i);
	}
	return false;
}

int solve(int n, int m, int DL[][MAXN], int maxdepth) {
	if (maxdepth > n) maxdepth = n;
	for (int i = 0; i <= m; i ++) {
		L[i] = i - 1;
		R[i] = i + 1;
		U[i] = D[i] = i;
	}
	L[0] = m;
	R[m] = 0;
	int cnt = m + 1;
	memset(S, 0, sizeof (S));
	for (int i = 1; i <= n; i ++) {
		int head = cnt, tail = cnt;
		for (int c = 1; c <= m; c ++) if (DL[i][c]) {
			S[c] ++;
			Col[cnt] = c;
			U[D[c]] = cnt;
			D[cnt] = D[c];
			U[cnt] = c;
			D[c] = cnt;
			L[cnt] = tail;
			R[tail] = cnt;
			R[cnt] = head;
			L[head] = cnt;
			tail = cnt;
			cnt ++;
		}
	}
	int best = 0, worst = maxdepth;
	/*while (best <= worst) {
		limit = (worst + best) >> 1;
		if (dfs(0)) worst = limit - 1;
		else best = limit + 1;
	}*/
	limit = maxdepth;
	if(dfs(0))best = maxdepth;
	else
		best = maxdepth+1;
	return best;
}

int x[155],y[155];

int dij(int i, int j)
{
	int d1 = (x[i]-x[j])*(x[i]-x[j]);
	int d2 = (y[i]-y[j])*(y[i]-y[j]);
	return d1+d2;
}

int main()
{
	int i,j,k,l,row,col,n,m,low,up,mid,mark[MAXN][MAXN],d[55][55],T,b[3000],top;
 
	scanf("%d",&T);
	while(T--)
	{
		scanf("%d %d %d",&n,&row,&m);

		for(i=1;i<=n+row;i++)
			scanf("%d %d",&x[i],&y[i]);
 
		low = 1; up = 1000000000;

		while(low < up)
		{
			for(i=1;i<=row;i++)
				for(j=1;j<=n;j++)mark[i][j] = 0;
   
			mid = (low + up)>>1;
			for(i=1;i<=row;i++)
				for(j=1;j<=n;j++)if(dij(i+n,j) <= mid)mark[i][j] = 1;
	
			if(solve(row, n, mark, m) > m)low = mid+1; else up = mid;
		}
		mid = (low + up)>>1;
		printf("%.6lf\n",sqrt(1.0*mid));
	}
	return 0;
}

dancing links code 1-3

一、fzu 1686
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#include<stdio.h>
#include<algorithm>

using namespace std;

const int MAXN = 225;
int L[MAXN*MAXN], R[MAXN*MAXN], U[MAXN*MAXN], D[MAXN*MAXN];
int S[MAXN];
int Col[MAXN*MAXN];
int limit;

void Remove(int x) {
	for (int i = D[x]; i != x; i = D[i]) {
		L[R[i]] = L[i];
		R[L[i]] = R[i];
	}
}
void Resume(int x) {
	for (int i = U[x]; i != x; i = U[i]) {
		L[R[i]] = R[L[i]] = i;
	}
}
int Hash() {
	int ans = 0;
	bool hash[MAXN] = {0};
	for (int c = R[0]; c != 0; c = R[c])
	if (! hash[c]) {
		hash[c] = true;
		ans ++;
		for (int i = D[c]; i != c; i = D[i])
			for (int j = R[i]; j != i; j = R[j])
				hash[Col[j]] = true;
	}
	return ans;
}

bool dfs(int depth) {
	if (depth + Hash() > limit) return false;
	if (R[0] == 0) return true;
	int i, j, c, minnum = INT_MAX;
	for (i = R[0]; i != 0; i = R[i]) {
		if (S[i] < minnum) {
			minnum = S[i];
			c = i;
		}
	}
	for (i = U[c]; i != c; i = U[i]) {
		Remove(i);
		for (j = R[i]; j != i; j = R[j]) Remove(j);
		if (dfs(depth + 1)) {
			for (j = L[i]; j != i; j = L[j]) Resume(j);
			Resume(i);
			return true;
		}
		for (j = L[i]; j != i; j = L[j]) Resume(j);
		Resume(i);
	}
	return false;
}

int solve(int n, int m, int DL[][MAXN], int maxdepth) {
	if (maxdepth > n) maxdepth = n;
	for (int i = 0; i <= m; i ++) {
		L[i] = i - 1;
		R[i] = i + 1;
		U[i] = D[i] = i;
	}
	L[0] = m;
	R[m] = 0;
	int cnt = m + 1;
	memset(S, 0, sizeof (S));
	for (int i = 1; i <= n; i ++) {
		int head = cnt, tail = cnt;
		for (int c = 1; c <= m; c ++) if (DL[i][c]) {
			S[c] ++;
			Col[cnt] = c;
			U[D[c]] = cnt;
			D[cnt] = D[c];
			U[cnt] = c;
			D[c] = cnt;
			L[cnt] = tail;
			R[tail] = cnt;
			R[cnt] = head;
			L[head] = cnt;
			tail = cnt;
			cnt ++;
		}
	}
	int best = 0, worst = maxdepth;
	while (best <= worst) {
		limit = (worst + best) >> 1;
		if (dfs(0)) worst = limit - 1;
		else best = limit + 1;
	}
	return best;
}

int main()
{
	int i,j,k,l,row,col,n,m,n1,m1,mark[MAXN][MAXN],a[33][33],id[33][33];
 
	while(scanf("%d %d",&n,&m) != EOF)
	{
		col = 0;
		for(i=1;i<=n;i++)
			for(j=1;j<=m;j++)
			{
				scanf("%d",&a[i][j]);
				id[i][j] = -1;
				if(a[i][j] == 1) { col++; id[i][j] = col; }
			}
		scanf("%d %d",&n1,&m1);

		row = 0;
		for(i=1;i<=n-n1+1;i++)
			for(j=1;j<=m-m1+1;j++)
			{
				row++;
				for(k=1;k<=col;k++)mark[row][k] = 0;
 
				for(k=i;k<i+n1;k++)
					for(l=j;l<j+m1;l++)
					if(id[k][l] > 0)
						mark[row][id[k][l]] = 1;
			}
 
		printf("%d\n",solve(row, col, mark, row));
	}
	return 0;
}

二、zju 3209
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#include<stdio.h>
#include<algorithm>
#include<math.h>
#include<string.h>

using namespace std;

const int MAXN = 1005;
int L[MAXN*MAXN], R[MAXN*MAXN], U[MAXN*MAXN], D[MAXN*MAXN];
int S[MAXN];
int Col[MAXN*MAXN], Row[MAXN*MAXN],ans,limit,up;


void Remove(int c) {
	L[R[c]] = L[c];
	R[L[c]] = R[c];
	for (int i = D[c]; i != c; i = D[i])
	for (int j = R[i]; j != i; j = R[j]) {
		U[D[j]] = U[j];
		D[U[j]] = D[j];
		-- S[Col[j]];
	}
}
void Resume(int c) {
	for (int i = U[c]; i != c; i = U[i])
	for (int j = L[i]; j != i; j = L[j]) {
		U[D[j]] = j;
		D[U[j]] = j;
		++ S[Col[j]];
	}
	L[R[c]] = c;
	R[L[c]] = c;
}

bool dfs(int depth) {
	if (depth >= ans) return true;
 
	if(R[0] == 0) { if(depth < ans)ans = depth;  return true; }
 
	int i, j, c, minnum = 2000000000, flag = 0;
	for (i = R[0]; i != 0; i = R[i]) {
		if (S[i] < minnum) {
			minnum = S[i];
			c = i;
		}
	}
	Remove(c);
	for (i = U[c]; i != c; i = U[i]) {
		//如果需要的话,在这里记录一组解(Ans[depth] = Row[i])
		for (j = R[i]; j != i; j = R[j]) Remove(Col[j]);
		if (dfs(depth + 1)) flag = 1; //return true;
		for (j = L[i]; j != i; j = L[j]) Resume(Col[j]);
	}
	Resume(c);
	return flag;//false;
}
int solve(int n, int m, int DL[][MAXN]) {
	for (int i = 0; i <= m; i ++) {
		L[i] = i - 1;
		R[i] = i + 1;
		U[i] = D[i] = i;
	}
	L[0] = m;
	R[m] = 0;
	int cnt = m + 1;
	memset(S, 0, sizeof (S));
	for (int i = 1; i <= n; i ++) {
		int head = cnt, tail = cnt;
		for (int c = 1; c <= m; c ++) if (DL[i][c]) {
			S[c] ++;
			Row[cnt] = i;
			Col[cnt] = c;
			U[D[c]] = cnt;
			D[cnt] = D[c];
			U[cnt] = c;
			D[c] = cnt;
			L[cnt] = tail;
			R[tail] = cnt;
			R[cnt] = head;
			L[head] = cnt;
			tail = cnt;
			cnt ++;
		}
	}
	if (dfs(0)) return true;
	return false;
}

int mark[MAXN][MAXN];

int main()
{
	int i,j,k,l,n,m,T,row,col,x1,x2,y1,y2,id[33][33],low;
	scanf("%d",&T);
	while(T--)
	{
		scanf("%d %d %d",&n,&m,&row);
		col = 0;
		for(i=1;i<=n;i++)
			for(j=1;j<=m;j++)
			{
				col++; id[i][j] = col;
			}
 
		for(i=1;i<=row;i++)
			for(j=1;j<=col;j++)mark[i][j] = 0;

		for(i=1;i<=row;i++)
		{
			scanf("%d %d %d %d",&x1,&y1,&x2,&y2);
			x1++; y1++;
			for(k=x1;k<=x2;k++)
				for(l=y1;l<=y2;l++)
				mark[i][id[k][l]] = 1;
		}

		ans = 1000000000;
		if(!solve(row, col, mark))ans = -1;

		printf("%d\n",ans);
	}
	return 0;
}

三、hdu 3529
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#include<stdio.h>
#include<algorithm>

using namespace std;

const int MAXN = 225;
int L[MAXN*MAXN], R[MAXN*MAXN], U[MAXN*MAXN], D[MAXN*MAXN];
int S[MAXN];
int Col[MAXN*MAXN];
int limit;

void Remove(int x) {
	for (int i = D[x]; i != x; i = D[i]) {
		L[R[i]] = L[i];
		R[L[i]] = R[i];
	}
}
void Resume(int x) {
	for (int i = U[x]; i != x; i = U[i]) {
		L[R[i]] = R[L[i]] = i;
	}
}
int Hash() {
	int ans = 0;
	bool hash[MAXN] = {0};
	for (int c = R[0]; c != 0; c = R[c])
	if (! hash[c]) {
		hash[c] = true;
		ans ++;
		for (int i = D[c]; i != c; i = D[i])
		for (int j = R[i]; j != i; j = R[j])
		hash[Col[j]] = true;
	}
	return ans;
}

bool dfs(int depth) {
	if (depth + Hash() > limit) return false;
	if (R[0] == 0) return true;
	int i, j, c, minnum = 2000000000;
	for (i = R[0]; i != 0; i = R[i]) {
		if (S[i] < minnum) {
			minnum = S[i];
			c = i;
		}
	}
	for (i = U[c]; i != c; i = U[i]) {
		Remove(i);
		for (j = R[i]; j != i; j = R[j]) Remove(j);
		if (dfs(depth + 1)) {
			for (j = L[i]; j != i; j = L[j]) Resume(j);
			Resume(i);
			return true;
		}
		for (j = L[i]; j != i; j = L[j]) Resume(j);
		Resume(i);
	}
	return false;
}

int solve(int n, int m, int DL[][MAXN], int maxdepth) {
	if (maxdepth > n) maxdepth = n;
	for (int i = 0; i <= m; i ++) {
			L[i] = i - 1;
			R[i] = i + 1;
			U[i] = D[i] = i;
		}
		L[0] = m;
		R[m] = 0;
		int cnt = m + 1;
		memset(S, 0, sizeof (S));
		for (int i = 1; i <= n; i ++) {
			int head = cnt, tail = cnt;
			for (int c = 1; c <= m; c ++) if (DL[i][c]) {
				S[c] ++;
				Col[cnt] = c;
				U[D[c]] = cnt;
				D[cnt] = D[c];
				U[cnt] = c;
				D[c] = cnt;
				L[cnt] = tail;
				R[tail] = cnt;
				R[cnt] = head;
				L[head] = cnt;
				tail = cnt;
				cnt ++;
			}
		}
		int best = 0, worst = maxdepth;
		while (best <= worst) {
		limit = (worst + best) >> 1;
		if (dfs(0)) worst = limit - 1;
		else best = limit + 1;
	}
	return best;
}

int n,m,M[MAXN][MAXN];

int main()
{
	int i,j,k,l,row,col,idr[33][33],idc[33][33];
   
	char ch[33][33];
	while(scanf("%d %d",&n,&m) != EOF)
	{
		for(i=1;i<=n;i++) scanf("%s",ch[i]+1);
	   
		row = col = 0;
	   
		for(i=1;i<=n;i++)
			for(j=1;j<=m;j++)
			if(ch[i][j] == '.') idr[i][j] = ++row;
			else
			if(ch[i][j] == '#') idc[i][j] = ++col;
		   
		for(i=0;i<=row;i++) for(j=0;j<=col;j++) M[i][j] = 0;
	   
		for(i=1;i<=n;i++)
			for(j=1;j<=m;j++)
			if(ch[i][j] == '.')
			{
				k = i-1; l = j; while(k > 0 && ch[k][l] == '.') k--;
				if(k > 0 && ch[k][l] == '#') M[idr[i][j]][idc[k][l]] = 1;
			   
				k = i+1; l = j; while(k <= n && ch[k][l] == '.') k++;
				if(k <= n && ch[k][l] == '#') M[idr[i][j]][idc[k][l]] = 1;
			   
				k = i; l = j-1; while(l > 0 && ch[k][l] == '.') l--;
				if(l > 0 && ch[k][l] == '#') M[idr[i][j]][idc[k][l]] = 1;
			   
				k = i; l = j+1; while(l <= m && ch[k][l] == '.') l++;
				if(l <= m && ch[k][l] == '#') M[idr[i][j]][idc[k][l]] = 1;
			}
		   
		int ans = solve(row, col, M, col);
		printf("%d\n",ans);
	}
	return 0;  
}

dancing links

Knuth Dancing_Links 中文版 http://www.docin.com/p-31928825.html

http://acm.fzu.edu.cn/problem.php?pid=1686

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3209

http://acm.hdu.edu.cn/showproblem.php?pid=3529

http://acm.hdu.edu.cn/showproblem.php?pid=3663

http://acm.hdu.edu.cn/showproblem.php?pid=2295

http://poj.org/problem?id=3074

http://poj.org/problem?id=3076

// fzu 1686
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#include<stdio.h>
#include<algorithm>

using namespace std;

const int MAXN = 225;
int L[MAXN*MAXN], R[MAXN*MAXN], U[MAXN*MAXN], D[MAXN*MAXN];
int S[MAXN];
int Col[MAXN*MAXN];
int limit;

void Remove(int x) {
	for (int i = D[x]; i != x; i = D[i]) {
	L[R[i]] = L[i];
	R[L[i]] = R[i];
	}
}
void Resume(int x) {
	for (int i = U[x]; i != x; i = U[i]) {
	L[R[i]] = R[L[i]] = i;
	}
}
int Hash() {
	int ans = 0;
	bool hash[MAXN] = {0};
	for (int c = R[0]; c != 0; c = R[c])
	if (! hash[c]) {
		hash[c] = true;
		ans ++;
		for (int i = D[c]; i != c; i = D[i])
		for (int j = R[i]; j != i; j = R[j])
		hash[Col[j]] = true;
	}
	return ans;
}

bool dfs(int depth) {
	if (depth + Hash() > limit) return false;
	if (R[0] == 0) return true;
	int i, j, c, minnum = INT_MAX;
	for (i = R[0]; i != 0; i = R[i]) {
		if (S[i] < minnum) {
			minnum = S[i];
			c = i;
		}
	}
	for (i = U[c]; i != c; i = U[i]) {
			Remove(i);
			for (j = R[i]; j != i; j = R[j]) Remove(j);
			if (dfs(depth + 1)) {
			for (j = L[i]; j != i; j = L[j]) Resume(j);
			Resume(i);
			return true;
		}
		for (j = L[i]; j != i; j = L[j]) Resume(j);
		Resume(i);
	}
	return false;
}

int solve(int n, int m, int DL[][MAXN], int maxdepth) {
	if (maxdepth > n) maxdepth = n;
	for (int i = 0; i <= m; i ++) {
		L[i] = i - 1;
		R[i] = i + 1;
		U[i] = D[i] = i;
	}
	L[0] = m;
	R[m] = 0;
	int cnt = m + 1;
	memset(S, 0, sizeof (S));
	for (int i = 1; i <= n; i ++) {
		int head = cnt, tail = cnt;
		for (int c = 1; c <= m; c ++) if (DL[i][c]) {
			S[c] ++;
			Col[cnt] = c;
			U[D[c]] = cnt;
			D[cnt] = D[c];
			U[cnt] = c;
			D[c] = cnt;
			L[cnt] = tail;
			R[tail] = cnt;
			R[cnt] = head;
			L[head] = cnt;
			tail = cnt;
			cnt ++;
		}
	}
	int best = 0, worst = maxdepth;
	while (best <= worst) {
		limit = (worst + best) >> 1;
		if (dfs(0)) worst = limit - 1;
		else best = limit + 1;
	}
	return best;
}

int main()
{
	int i,j,k,l,row,col,n,m,n1,m1,mark[MAXN][MAXN],a[33][33],id[33][33];

	while(scanf("%d %d",&n,&m) != EOF)
	{
		col = 0;
		for(i=1;i<=n;i++)
			for(j=1;j<=m;j++)
			{
				scanf("%d",&a[i][j]);
				id[i][j] = -1;
				if(a[i][j] == 1) { col++; id[i][j] = col; }
			}
		scanf("%d %d",&n1,&m1);

		row = 0;
		for(i=1;i<=n-n1+1;i++)
			for(j=1;j<=m-m1+1;j++)
			{
				row++;
				for(k=1;k<=col;k++)mark[row][k] = 0;
			
				for(k=i;k<i+n1;k++)
					for(l=j;l<j+m1;l++)
					if(id[k][l] > 0)
						mark[row][id[k][l]] = 1;
			}
		
		printf("%d\n",solve(row, col, mark, row));
	}
	return 0;
}
// hdu 2295
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#include<stdio.h>
#include<algorithm>
#include<math.h>
#include<string.h>

using namespace std;

const int MAXN = 225;
int L[MAXN*MAXN], R[MAXN*MAXN], U[MAXN*MAXN], D[MAXN*MAXN];
int S[MAXN];
int Col[MAXN*MAXN];
int limit;

void Remove(int x) {
	for (int i = D[x]; i != x; i = D[i]) {
	L[R[i]] = L[i];
	R[L[i]] = R[i];
	}
}
void Resume(int x) {
	for (int i = U[x]; i != x; i = U[i]) {
	L[R[i]] = R[L[i]] = i;
	}
}
int Hash() {
	int ans = 0;
	bool hash[MAXN] = {0};
	for (int c = R[0]; c != 0; c = R[c])
	if (! hash[c]) {
		hash[c] = true;
		ans ++;
		for (int i = D[c]; i != c; i = D[i])
		for (int j = R[i]; j != i; j = R[j])
		hash[Col[j]] = true;
	}
	return ans;
}

bool dfs(int depth) {
	if (depth + Hash() > limit) return false;
	if (R[0] == 0) return true;
	int i, j, c, minnum = 2000000000;
	for (i = R[0]; i != 0; i = R[i]) {
		if (S[i] < minnum) {
			minnum = S[i];
			c = i;
		}
	}
	for (i = U[c]; i != c; i = U[i]) {
			Remove(i);
			for (j = R[i]; j != i; j = R[j]) Remove(j);
			if (dfs(depth + 1)) {
			for (j = L[i]; j != i; j = L[j]) Resume(j);
			Resume(i);
			return true;
		}
		for (j = L[i]; j != i; j = L[j]) Resume(j);
		Resume(i);
	}
	return false;
}

int solve(int n, int m, int DL[][MAXN], int maxdepth) {
	if (maxdepth > n) maxdepth = n;
	for (int i = 0; i <= m; i ++) {
		L[i] = i - 1;
		R[i] = i + 1;
		U[i] = D[i] = i;
	}
	L[0] = m;
	R[m] = 0;
	int cnt = m + 1;
	memset(S, 0, sizeof (S));
	for (int i = 1; i <= n; i ++) {
		int head = cnt, tail = cnt;
		for (int c = 1; c <= m; c ++) if (DL[i][c]) {
			S[c] ++;
			Col[cnt] = c;
			U[D[c]] = cnt;
			D[cnt] = D[c];
			U[cnt] = c;
			D[c] = cnt;
			L[cnt] = tail;
			R[tail] = cnt;
			R[cnt] = head;
			L[head] = cnt;
			tail = cnt;
			cnt ++;
		}
	}
	int best = 0, worst = maxdepth;
	/*while (best <= worst) {
		limit = (worst + best) >> 1;
		if (dfs(0)) worst = limit - 1;
		else best = limit + 1;
	}*/
	limit = maxdepth;
	if(dfs(0))best = maxdepth;
	else
		best = maxdepth+1;
	return best;
}

int x[155],y[155];

int dij(int i, int j)
{
	int d1 = (x[i]-x[j])*(x[i]-x[j]);
	int d2 = (y[i]-y[j])*(y[i]-y[j]);
	return d1+d2;
}

int main()
{
	int i,j,k,l,row,col,n,m,low,up,mid,mark[MAXN][MAXN],d[55][55],T,b[3000],top;


	scanf("%d",&T);
	while(T--)
	{
		scanf("%d %d %d",&n,&row,&m);

		for(i=1;i<=n+row;i++)
			scanf("%d %d",&x[i],&y[i]);
	
		low = 1; up = 1000000000;

		while(low < up)
		{
			for(i=1;i<=row;i++)
				for(j=1;j<=n;j++)mark[i][j] = 0;
		
			mid = (low + up)>>1;
			for(i=1;i<=row;i++)
				for(j=1;j<=n;j++)if(dij(i+n,j) <= mid)mark[i][j] = 1;
			
			if(solve(row, n, mark, m) > m)low = mid+1; else up = mid;
		}
		mid = (low + up)>>1;
		printf("%.6lf\n",sqrt(1.0*mid));
	}
	return 0;
}

划分树--查询区间k-th number code

一、pku_2104
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#include<stdio.h>
#include<algorithm>

#define N 100000+100
#define M 21  // log(N)

using namespace std;

struct Node {
	int val,id;
} a[N];

int n,m,tr[M][N];

int cmp(Node aa, Node bb) {
	if(aa.val < bb.val || (aa.val == bb.val && aa.id < bb.id)) return 1;
	return 0;
}

void build_tree(int dep, int s, int t)
{
	if(s >= t) return;
	
	int i,j,k,mid = (s+t)/2;
	j = s; k = mid+1;
	
	for(i=s;i<=t;i++)
	{
	    if(tr[dep][i] <= mid)
	        tr[dep+1][j++] = tr[dep][i];
	    else
	        tr[dep+1][k++] = tr[dep][i];

	    tr[dep][i] = j-1;
	}
	
	build_tree(dep+1, s, mid);
	build_tree(dep+1, mid+1, t);
}

int find_tree(int dep, int s, int t, int i, int j, int k)
{
	if(s == t) return s;
	int ci, mid = (s+t)/2;
	
	int v = tr[dep][j]-(s-1);
	if(i > s) v = tr[dep][j] - tr[dep][i-1];
	
	if(v >= k)
	{
	    ci = s; if(i > s) ci = tr[dep][i-1]+1;
	    return find_tree(dep+1, s, mid, ci, tr[dep][j], k);
	}
	else
	{
	    ci = mid+1; if(i > s) ci = mid+1 + (i-1)-tr[dep][i-1];
	    return find_tree(dep+1, mid+1, t, ci, mid+j-tr[dep][j], k-v);
	}
	return 0;
}

int main()
{
	int i,j,k,ans;
	while(scanf("%d %d",&n,&m) != EOF)
	{
	    for(i=1;i<=n;i++) {
	        scanf("%d",&a[i].val); a[i].id = i;
	    }
	    
	    sort(a+1, a+1+n, cmp);
	    for(i=1;i<=n;i++) tr[0][a[i].id] = i;

	    build_tree(0, 1, n);
	    
	    while(m--)
	    {
	        scanf("%d %d %d",&i,&j,&k);
	        ans = find_tree(0, 1, n, i, j, k);
	        printf("%d\n",a[ans].val);
	    }
	}
	return 0;
}

二、hdu_2665
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#include<stdio.h>
#include<algorithm>

#define N 100000+100
#define M 21  // log(N)

using namespace std;

struct Node {
	int val,id;
} a[N];

int n,m,tr[M][N];

int cmp(Node aa, Node bb) {
	if(aa.val < bb.val || (aa.val == bb.val && aa.id < bb.id)) return 1;
	return 0;
}

void build_tree(int dep, int s, int t)
{
	if(s >= t) return;
   
	int i,j,k,mid = (s+t)/2;
	j = s; k = mid+1;
   
	for(i=s;i<=t;i++)
	{
	    if(tr[dep][i] <= mid)
	        tr[dep+1][j++] = tr[dep][i];
	    else
	        tr[dep+1][k++] = tr[dep][i];

	    tr[dep][i] = j-1;
	}
   
	build_tree(dep+1, s, mid);
	build_tree(dep+1, mid+1, t);
}

int find_tree(int dep, int s, int t, int i, int j, int k)
{
	if(s == t) return s;
	int ci, mid = (s+t)/2;
   
	int v = tr[dep][j]-(s-1);
	if(i > s) v = tr[dep][j] - tr[dep][i-1];
   
	if(v >= k)
	{
	    ci = s; if(i > s) ci = tr[dep][i-1]+1;
	    return find_tree(dep+1, s, mid, ci, tr[dep][j], k);
	}
	else
	{
	    ci = mid+1; if(i > s) ci = mid+1 + (i-1)-tr[dep][i-1];
	    return find_tree(dep+1, mid+1, t, ci, mid+j-tr[dep][j], k-v);
	}
	return 0;
}

int main()
{
	int i,j,k,ans,T;
	scanf("%d",&T);
	while(T--)
	{
	    scanf("%d %d",&n,&m);
	    for(i=1;i<=n;i++) {
	        scanf("%d",&a[i].val); a[i].id = i;
	    }
	   
	    sort(a+1, a+1+n, cmp);
	    for(i=1;i<=n;i++) tr[0][a[i].id] = i;

	    build_tree(0, 1, n);
	   
	    while(m--)
	    {
	        scanf("%d %d %d",&i,&j,&k);
	        ans = find_tree(0, 1, n, i, j, k);
	        printf("%d\n",a[ans].val);
	    }
	}
	return 0;
}

三、hdu_3727
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#include<stdio.h>
#include<algorithm>

#define N 100000+100
#define M 21  // log(N)

typedef long long LL;

using namespace std;

struct Input {
	int sta,s,t,k;
} q[N+N+N];

struct Node {
	int val,id;
} a[N];

int n,m,tr[M][N],C[N],b[N];

int cmp(Node aa, Node bb) {
	if(aa.val < bb.val || (aa.val == bb.val && aa.id < bb.id)) return 1;
	return 0;
}

int lowbit(int x) {
	return x&(-x);
}

void change(int x, int y) {
	while(x <= n) {
	    C[x] += y; x += lowbit(x);
	}
}

int cal(int x) {
	int t=0;
	while(x > 0) {
	    t += C[x]; x -= lowbit(x);
	}
	return t;
}

void build_tree(int dep, int s, int t)
{
	if(s >= t) return;
   
	int i,j,k,mid = (s+t)/2;
	j = s; k = mid+1;
   
	for(i=s;i<=t;i++)
	{
	    if(tr[dep][i] <= mid)
	        tr[dep+1][j++] = tr[dep][i];
	    else
	        tr[dep+1][k++] = tr[dep][i];

	    tr[dep][i] = j-1;
	}
   
	build_tree(dep+1, s, mid);
	build_tree(dep+1, mid+1, t);
}

int find_tree(int dep, int s, int t, int i, int j, int k)
{
	if(s == t) return s;
	int ci, mid = (s+t)/2;
   
	int v = tr[dep][j]-(s-1);
	if(i > s) v = tr[dep][j] - tr[dep][i-1];
   
	if(v >= k)
	{
	    ci = s; if(i > s) ci = tr[dep][i-1]+1;
	    return find_tree(dep+1, s, mid, ci, tr[dep][j], k);
	}
	else
	{
	    ci = mid+1; if(i > s) ci = mid+1 + (i-1)-tr[dep][i-1];
	    return find_tree(dep+1, mid+1, t, ci, mid+j-tr[dep][j], k-v);
	}
	return 0;
}

int main()
{
	int i,k,T,low,up,mid,cas=0;
	LL ans[5];
	char ch[33];
   
	while(scanf("%d",&T) != EOF)
	{
	   
	    n = 0; m = 0;
	    for(i=1;i<=T;i++)
	    {
	        scanf("%s", ch);
	        if(ch[0] == 'I')
	        {
	            q[i].sta = 0;
	            n++; scanf("%d", &a[n].val); a[n].id = n;
	        }
	        else
	        {
	            q[i].sta = ch[6] - 48;
	            if(ch[6] == '1') scanf("%d %d %d",&q[i].s,&q[i].t,&q[i].k);
	            else
	                scanf("%d",&q[i].k);
	        }
	    }
	   
	    sort(a+1, a+1+n, cmp);
	    for(i=1;i<=n;i++)
	    {
	        b[a[i].id] = tr[0][a[i].id] = i;
	        C[i] = 0;
	    }
	    C[0] = 0;

	    build_tree(0, 1, n);
	   
	    ans[1] = ans[2] = ans[3] = 0;
	   
	    m = 0;
	   
	    for(i=1;i<=T;i++)
	    {
	        if(q[i].sta == 0)
	        {
	            m++;
	            change(b[m], 1);
	        }
	        else
	        if(q[i].sta == 1)
	        {
	            k = find_tree(0, 1, n, q[i].s, q[i].t, q[i].k);
	            ans[1] += a[k].val;
	        }
	        else
	        if(q[i].sta == 2)
	        {
	            low = 1; up = n;
	            while(low < up) {
	                mid = (low + up)/2;
	                if(a[mid].val < q[i].k) low = mid+1; else up = mid;
	            }
	            mid = (low + up)/2;
	            ans[2] += cal(mid);
	        }
	        else
	        if(q[i].sta == 3)
	        {
	            low = 1; up = n;
	            while(low < up) {
	                mid = (low + up)/2;
	                if(cal(mid) < q[i].k) low = mid+1; else up = mid;
	            }
	            mid = (low + up)/2;
	            ans[3] += a[mid].val;
	        }
	    }
	    cas++;
	    printf("Case %d:\n%lld\n%lld\n%lld\n",cas,ans[1],ans[2],ans[3]);
	}
	return 0;
}

四、hdu_3473
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#include<stdio.h>
#include<algorithm>

#define N 100000+100
#define M 21  // log(N)

typedef long long LL;

using namespace std;

struct Node {
	int val,id;
} a[N];

int n,m,pos,tr[M][N];
LL less,more, sum[M][N];

int cmp(Node aa, Node bb) {
	if(aa.val < bb.val || (aa.val == bb.val && aa.id < bb.id)) return 1;
	return 0;
}

void build_tree(int dep, int s, int t)
{
	if(s >= t) return;
   
	int i,j,k, mid = (s+t)/2;
	LL s1,s2;
   
	j = s; k = mid+1;
	s1 = s2 = 0;
   
	for(i=s;i<=t;i++)
	{
	    if(tr[dep][i] <= mid)
	    {
	        s1 += a[tr[dep][i]].val;
	        sum[dep][j] = s1;
	        tr[dep+1][j++] = tr[dep][i];
	    }
	    else
	    {
	        s2 += a[tr[dep][i]].val;
	        sum[dep][k] = s2;
	        tr[dep+1][k++] = tr[dep][i];
	    }

	    tr[dep][i] = j-1;
	}
   
	build_tree(dep+1, s, mid);
	build_tree(dep+1, mid+1, t);
}

void find_tree(int dep, int s, int t, int i, int j, int k)
{
	if(s == t) { pos = s; return ; }
	int ci,cj,  mid = (s+t)/2;
	LL s1,s2;
   
	int v = tr[dep][j]-(s-1);
	if(i > s) v = tr[dep][j] - tr[dep][i-1];
   
	if(v >= k)
	{
	    ci = s; if(i > s) ci = tr[dep][i-1]+1;
	    find_tree(dep+1, s, mid, ci, tr[dep][j], k);
	   
	   
	    if(i == s) ci = 0; else ci = (i-1)-tr[dep][i-1];
	    if(ci == 0) s1 = 0; else s1 = sum[dep][mid+ci];
	   
	    cj = j-tr[dep][j];
	    if(cj == 0) s2 = 0; else s2 = sum[dep][mid+cj];
	   
	    more += (s2-s1);
	}
	else
	{
	    ci = mid+1; if(i > s) ci = mid+1 + (i-1)-tr[dep][i-1];
	    find_tree(dep+1, mid+1, t, ci, mid+j-tr[dep][j], k-v);
	   
	   
	    if(i > s) ci = tr[dep][i-1]; else ci = s-1;
	    if(ci < s) s1 = 0; else s1 = sum[dep][ci];
	   
	    cj = tr[dep][j]; 
	    if(cj < s) s2 = 0; else s2 = sum[dep][cj];
	   
	    less += (s2-s1);
	}
}

int main()
{
	int i,j,k,T,cas=0;
	scanf("%d",&T);
	while(T--)
	{
	    scanf("%d",&n);
	    for(i=1;i<=n;i++) {
	        scanf("%d",&a[i].val); a[i].id = i;
	    }
	   
	    sort(a+1, a+1+n, cmp);
	   
	    sum[0][0] = 0;
	    for(i=1;i<=n;i++)
	    {
	        tr[0][a[i].id] = i;
	        sum[0][i] = sum[0][i-1] + a[i].val;
	    }

	    build_tree(0, 1, n);
	   
	    cas++;
	    printf("Case #%d:\n", cas);
	   
	    scanf("%d",&m);
	    while(m--)
	    {
	        scanf("%d %d",&i,&j);
	        i++; j++; k = (j-i+2)/2;
	        less = 0; more = 0;
	        find_tree(0, 1, n, i, j, k);
	       
	        //printf("%d %lld %lld\n",a[pos].val,less,more);
	       
	        printf("%lld\n", (LL)(k-1)*(LL)a[pos].val-less + more-(LL)(j-i+1-k)*(LL)a[pos].val);
	    }
	    printf("\n");
	}
	return 0;
}

划分树--查询区间k-th number

划分树 – 查询区间 k-th number

http://poj.org/problem?id=2104
http://acm.hdu.edu.cn/showproblem.php?pid=2665
http://acm.hdu.edu.cn/showproblem.php?pid=3727
http://acm.hdu.edu.cn/showproblem.php?pid=3473

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tr[ log(N) ][ N ]
1. 先对原来的数 稳定排序 ,tr[0][i] = 原先的数 a[i] 在排序后的位置。
2. dep = 0; s = 1; t = n;
3. 递归建树 
build_tree(dep, s, t)
{
    if(s >= t) return;
    mid = (s+t)/2;  j = s;  k = mid+1;
    for(i=s;i<=t;i++) if( tr[dep][i] <= mid )  tr[dep+1][j++] = tr[dep][i]; else tr[dep+1][k++] = tr[dep][i];
    //  把s 到 t 一分为二, s 到 t 的每个数 如果排序后它排在该区间的前半部分就移到下一层的前半部。
    //  如果要计算小于和大于 k-th number 的数的和要多算 sum[dep][x] 即 dep+1 层中 s 到 x(x<=mid) 的和 或 mid+1 到 x(x>mid) 的和。
    tr[dep][i] = j-1;  // s 到 t 区间, tr[dep][i] 记录 s 到 i 分到前半部分的最后位置
    build_tree(dep+1, s, mid);  build_tree(dep+1, mid+1, t);
}
4. 查找区间 [i,j] 中的 k-th number ,其中 1<=k<=j-i+1;
find_tree(dep, s, t, i, j, k)
{
    if(s == t) return s;
    v = i 到 j 中分到左边的数
    if(v >= k) return find_tree(dep+1, s, mid, ci, cj, k); // ci, cj 对应 i, j 分到前半部分的位置。 分到右半部分的和加到大于k-th number 上
    else    return find_tree(dep+1, mid+1, t, ci, cj, k-v); // 分到左半部分的和加到小于k-th number 上
 }
 
时间复杂度 O( n*log(n) 预处理, log(n) 查询 ) ,空间大小 n*log(n)
 
序列 : 2 5 9 8 4 3 1
排序后  1 2 3 4 5 8 9
所以 原序列对应的最终位置为 2 5 7 6 4 3 1
 
        按最终位置分                                   指向分到前半部分的最后位置
tr[0][] = 2 5 7 6 4 3 1                        处理后 tr[0][] = 1 1 1 1 2 3 4
tr[1][] = 2 4 3 1 || 5 7 6                            tr[1][] = 1 1 1 2 || 5 5 6
tr[2][] = 2 1 || 4 3 || 5 6 || 7                      tr[2][] = 0 1 || 2 3 || 5 5 || 7
tr[3][] = 1 || 2 || 3 || 4 || 5 || 6