sap模板

int dfs(int x,int flow){if(x==T) return flow;int tmp=res=0;for(int i=last[x];i;i=next[i]) if (d[x]==d[v[i]]+1 && w[i]>0){last[x]=i;tmp=dfs(v[i],min(flow-res,w[i]);res+=tmp;w[i]-=tmp;w[i^1]+=tmp;if (res==flow) return flow;}if (d[1]>=n) return res;vd[d[x]]--; if (vd[d[x]]==0) d[1]=n;d[x]++;vd[d[x]]++;last[x]=top[x];        return res;}int SAP{memset(d,0,sizeof(d));memset(vd,0,sizeof(vd);for (int i=1;i<=n;i++) last[i]=top[i];int ans=0;while (d[1]<n) ans+=dfs(S,1e9);return ans;}