pku 1469 COURSES(二分匹配)

 

http://acm.pku.edu.cn/JudgeOnline/problem?id=1469

 

题目大意：学生要选修选修课，给你P个选修课，每个选修课如果都被选中了，就输出YSE，否则NO。

 

解题思路：二分匹配入门题

 

#include <iostream>#include <vector>#include <string.h>#include <stdio.h>#define Max 1005using namespace std;bool visited[Max];int Match[Max];int P,N;vector<int>List[Max];void InputData(){int i,num,val;scanf("%d%d",&P,&N);for (i=1;i<=P;i++){scanf("%d",&num);while (num--){scanf("%d",&val);List[i].push_back(val);}}}bool DFS(int locate){int i,j,len = List[locate].size();for (i=0;i<len;i++){j = List[locate][i];if (!visited[j]){visited[j] = 1;if (Match[j]==-1||DFS(Match[j])){Match[j] = locate;return true;}}}return false;}int main(){int test,i,count;scanf("%d",&test);while (test--){InputData();count = 0;memset(Match,-1,sizeof(Match));for (i=1;i<=P;i++){memset(visited,0,sizeof(visited));if(DFS(i))count++;}if(count==P)printf("YES/n");elseprintf("NO/n");for(i=1;i<=P;i++)List[i].clear();}return 0;}