Dinic算法网络流模板
#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
#define maxn 1000
#define min(x,y) x<y?x:y
int n,m,map[maxn][maxn],dep[maxn],start,end;
queue<int> Q;
void clear()
{
memset(map,0,sizeof(int));
}
int bfs(int src)
{
while(!Q.empty()) Q.pop();
memset(dep,-1,sizeof(int));
Q.push(src),dep[src]=1;
while(!Q.empty())
{
int now=Q.front();
Q.pop();visit[now]=1;
if(now==end) break;
for(int i=1;i<=n;i++)
if(map[now][i]>0&&dep[i]==-1)
dep[i]=dep[now]+1,Q.push(i);
}
if(dep[end]==-1) return 0;
else return 1;
}
int dfs(int src,int flow)
{
int temp;
if(src==end) return 1;
for(int i=1;i<=n;i++)
if(map[src][i]>0&&dep[src]==dep[i]+1&&(temp=dfs(i,min(flow,map[src][i]))))
{
map[src][i]-=temp;
map[i][src]+=temp;
return temp;//这里差点漏写
}
return 0;
}
int dinic()
{
int maxxx=99999999,ans=0;
while(bfs(1))
{
int temp=dfs(start,maxxx);
if(!temp) break;
ans+=temp;
}
return ans;
}
int main()
{
int x,y,z;
clear();
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++)
{
scanf("%d%d%d",&x,&y,&z);
map[x][y]+=z;
map[y][x]-=z;
}
start=1,end=m;
printf("%d\n",dinic());
}