CodeForcesGym 100753B Bounty Hunter II

Bounty Hunter II

Time Limit: 5000ms

Memory Limit: 262144KB

This problem will be judged on CodeForcesGym. Original ID: 100753B
64-bit integer IO format: %I64d      Java class name: (Any)

解题：最小路径覆盖

 #include <bits/stdc++.h>
 using namespace std;
 const int maxn = ;
 vector<int>g[maxn];
 int Link[maxn],n;
 bool used[maxn];
 bool match(int u){
     for(int i = g[u].size()-; i >= ; --i){
         if(used[g[u][i]]) continue;
         used[g[u][i]] = true;
         if(Link[g[u][i]] == - || match(Link[g[u][i]])){
             Link[g[u][i]] = u;
             return true;
         }
     }
     return false;
 }
 int main(){
     int m;
     while(~scanf("%d",&n)){
         for(int i = ; i < maxn; ++i) g[i].clear();
         for(int i = ; i < n; ++i){
             scanf("%d",&m);
             for(int j = ,v; j < m; ++j){
                 scanf("%d",&v);
                 g[i].push_back(v + n);
             }
         }
         memset(Link,-,sizeof Link);
         int ret = ;
         for(int i = ; i < n; ++i){
             memset(used,false,sizeof used);
             if(match(i)) ++ret;
         }
         printf("%d\n",n - ret);
     }
 }
 /*
 4
 1 1
 1 2
 0
 1 1

 6
 0
 1 2
 2 4 5
 1 2
 0
 0

 5
 1 4
 1 4
 1 4
 1 4
 0
 */