http://acm.hdu.edu.cn/showproblem.php?pid=3549
题解:
网络流最大流
Dinic 算法
参考文章:https://blog.csdn.net/txl199106/article/details/64441994
/*
*@Author: STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
#define endl "\n"
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=100+10;
const int M=100000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,p,l,r,u,v;
int ans,cnt,flag,temp,sum;
int dis[N];
int mp[N][N];
char str;
struct node{
int v,c;
};
bool bfs(int u){
memset(dis,-1,sizeof(dis));
dis[u]=0;
queue<int>q;
q.push(u);
while(!q.empty()){
int u=q.front();
q.pop();
for(int i=1;i<=n;i++){
if(dis[i]<0&&mp[u][i]>0){
dis[i]=dis[u]+1;
q.push(i);
}
}
}
return dis[n]>0;
}
int dfs(int u,int flow){
if(u==n)
return flow;
int now;
for(int i=1;i<=n;i++){
if(mp[u][i]>0&&dis[u]+1==dis[i]&&(now=dfs(i,min(flow,mp[u][i])))){
mp[u][i]-=now;
mp[i][u]+=now;
return now;
}
}
return 0;
}
void dinic(){
while(bfs(1)){
ans+=dfs(1,INF);
}
}
void init(){
memset(mp,0,sizeof(mp));
ans=0;
}
int main()
{
#ifdef DEBUG
freopen("input.in", "r", stdin);
//freopen("output.out", "w", stdout);
#endif
//ios::sync_with_stdio(false);
//cin.tie(0);
//cout.tie(0);
scanf("%d",&t);
int T=0;
while(t--){
scanf("%d%d",&n,&m);
init();
for(int i=1;i<=m;i++){
scanf("%d%d%d",&u,&v,&k);
mp[u][v]+=k;
}
dinic();
printf("Case %d: %d\n",++T,ans);
}
#ifdef DEBUG
printf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC);
#endif
//cout << "Hello world!" << endl;
return 0;
}