hdu3549(最大流ford-fulkerson模板)

题意：

给你一个有向图，源点为1，汇点为n，求最大流。

思路：

ford-fulkerson模板

代码：

#include <bits/stdc++.h>using namespace std;const int maxn = 20;const int inf = 0x3f3f3f3f;class edge{public:    int to,cap,rev;    edge(int t,int c,int r)    {        to = t;        cap = c;        rev = r;    }};int vis[maxn];vector<edge> g[maxn];void add(int from,int to,int cap){    g[from].push_back(edge(to,cap,g[to].size()));    g[to].push_back(edge(from,0,g[from].size()-1));}int dfs(int u,int t,int f){    if(u==t)        return f;    vis[u] = 1;    for(int i = 0;i<g[u].size();i++)    {        edge &e = g[u][i];        if(!vis[e.to]&&e.cap>0)        {            int d = dfs(e.to,t,min(f,e.cap));            if(d>0)            {                e.cap-=d;                g[e.to][e.rev].cap+=d;                return d;            }        }    }    return 0;}int ford_fulkerson(int s,int t){    int ans = 0;    while(1)    {        memset(vis,0,sizeof(vis));        int f = dfs(s,t,inf);        if(f==0)            return ans;        ans += f;    }    return ans;}int main(){    int t,kase = 1;    cin>>t;    while(t--)    {        int n,m;        scanf("%d%d",&n,&m);        for(int i = 1;i<=n;i++)        {            g[i].clear();        }        for(int i = 0;i<m;i++)        {            int u,v,val;            scanf("%d%d%d",&u,&v,&val);            add(u,v,val);        }        printf("Case %d: %d\n",kase++,ford_fulkerson(1,n));    }    return 0;}