模板——Dinic
震惊,照着SYCstudio的教程打出来的Dinic竟被呆滞怒斥是EK,惊了,打开教程的方式可能跟呆滞不太一样。
#include<bits/stdc++.h> using namespace std; const int P=1000000007; int n,m,s,t,jump[100005]={0},num=1,deep[100005]; struct edge{ int to,val,jump; }a[200005]; void add(int x,int y,int z){ num++; a[num].jump=jump[x]; jump[x]=num; a[num].to=y; a[num].val=z; } bool bfs(){ queue<int> q; while (!q.empty()) q.pop(); for (int i=1; i<=n; i++) deep[i]=0; deep[s]=1; q.push(s); while (!q.empty()){ int pos=q.front(); q.pop(); for (int i=jump[pos]; i; i=a[i].jump){ if (!deep[a[i].to] && a[i].val>0){ deep[a[i].to]=deep[pos]+1; q.push(a[i].to); } } } return deep[t]!=0; } int dfs(int pos,int len){ if (pos==t) return len; int used=0,w=0; for (int i=jump[pos]; i; i=a[i].jump){ if (deep[a[i].to]==deep[pos]+1 && a[i].val>0){ w=len-used; int le=dfs(a[i].to,min(w,a[i].val)); a[i].val-=le; a[i^1].val+=le; used+=le; if(used==len) return len; } } if (!s) deep[pos]=0; return used; } int main(){ int ans=0; scanf("%d%d%d%d",&n,&m,&s,&t); for (int i=1,x,y,z; i<=m; i++){ scanf("%d%d%d",&x,&y,&z); add(x,y,z); add(y,x,0); } int d; while (bfs()){ ans+=dfs(s,P); } printf("%d",ans); return 0; }