Bzoj 1059: [zjoi2007] matrix game Bipartite Graph Matching

1059: [zjoi2007] matrix game time limit: 10 sec memory limit: 162 MB
Submit: 1891 solved: 919
[Submit] [Status] Description

Q is a very smart child. In addition to chess, he also enjoys playing a computer puzzle game, matrix game. Matrix games are played in an N * n black/white matrix (just like playing chess, the color is random ). You can perform two operations on the matrix each time: Row exchange operation: select any two rows of the matrix and exchange the two rows (that is, swap the color of the corresponding grid) column exchange operation: select any row and column of the Matrix, and exchange the two columns (that is, swap the color of the corresponding grid) to the game's target, that is, through several operations, the main diagonal line of the matrix (the line from the upper left to the lower right corner) the grid on is black. Q cannot solve certain levels, so that he began to doubt whether these levels are completely unsolvable !! Therefore, Xiao Q decided to write a program to determine whether these levels were resolved.

Input

The first line contains an integer T, indicating the number of data groups. Next, the data contains t groups. The first behavior of each group is an integer N, indicating the size of the square matrix. The next n behavior is an 01 matrix of N * n (0 indicates white, and 1 indicates black ).

Output

The output file should contain t rows. For each group of data, if the level is resolved, a row of yes is output; otherwise, a row of no is output.

Sample input2
2
0 0
0 1
3
0 0 1
0 1 0
1 0 0
Sample outputno
Yes
[Data scale]
For 20% of the data, n ≤ 7
For 50% of the data, n ≤ 50
For 100% of data, n ≤ 200
The hint Hungary algorithm is a bit forgotten. This kind of board conversion problem does not have to go to the target board. You just need to find the rule.

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#include<vector>using namespace std;#define MAXN 300vector<int> V[MAXN];int vis[MAXN];int pat[MAXN];int find(int x){    int i;    for (i=0;i<V[x].size();i++)    {        if (vis[V[x][i]])continue;        vis[V[x][i]]=true;        if (pat[V[x][i]]==-1||find(pat[V[x][i]]))        {            pat[V[x][i]]=x;            return 1;        }    }    return 0;}int main(){    freopen("input.txt","r",stdin);    //freopen("output.txt","w",stdout);    int nn,n,m;    int i,j,k;    int x;    int tot;    scanf("%d",&nn);    while (nn--)    {        scanf("%d",&n);        for (i=0;i<n;i++)        {            for (j=0;j<n;j++)            {                scanf("%d",&x);                if (x)V[i].push_back(j);            }        }        tot=0;        memset(pat,-1,sizeof(pat));        for (i=0;i<n;i++)        {            memset(vis,0,sizeof(vis));            tot+=find(i);        }        if (tot==n)        {            printf("Yes\n");        }else        {            printf("No\n");        }        for(i=0;i<n;i++)V[i].clear();    }}