poj1274 The Perfect Stall (匈牙利演算法)

匈牙利演算法模板題目

大牛的blog  http://www.byvoid.com/blog/hungary/

#include<iostream>#include<cstring>#include<cstdio>using namespace std;bool a[205][205];int mat[205];bool used[205];int n,m;bool crosspath(int k){int i;for(i=1;i<=m;i++){if(!used[i]&&a[k][i]==1){used[i]=1;if(mat[i]==0||crosspath(mat[i])){   //需要理解mat[i]=k;return 1;}}}return 0;}int main(){int si,stall;int i,j;while(scanf("%d%d",&n,&m)!=EOF){memset(a,0,sizeof(a));memset(mat,0,sizeof(mat));for(i=1;i<=n;i++){scanf("%d",&si);for(j=1;j<=si;j++){scanf("%d",&stall);a[i][stall]=1;}}int match=0;for(i=1;i<=n;i++){memset(used,0,sizeof(used));if(crosspath(i))match++;   //每一次成功的增廣路查詢都會使匹配加1}printf("%d\n",match);}return 0;}

另一種圖的儲存方法

#include<iostream>#include<cstring>#include<cstdio>using namespace std;bool used[205];int mat[205];int n,m;int a[410][410];bool crosspath(int k){int i,cur;for(i=1;i<=a[k][0];i++){cur=a[k][i];if(!used[cur]){used[cur]=1;if(mat[cur]==0||crosspath(mat[cur])){mat[cur]=k;return 1;}}}return 0;}int main(){int i,j;int si,stall;while(scanf("%d%d",&n,&m)!=EOF){memset(mat,0,sizeof(mat));memset(a,0,sizeof(a));for(i=1;i<=n;i++){scanf("%d",&si);a[i][0]=si;for(j=1;j<=si;j++){scanf("%d",&stall);a[i][j]=stall;}}int ans=0;for(i=1;i<=n;i++){memset(used,0,sizeof(used));if(crosspath(i))ans++;}printf("%d\n",ans);}return 0;}