hdu 1532 Drainage Ditches (最大流EK算法)

#include<stdio.h>
#include<string.h>
#define N 210
#define inf 10000010
int min(int a,int b){
return a<b?a:b;
}
int r

,n,flow;
int vis
,pre
,Q
;
int bfs(int s,int t){
memset(pre,-1,sizeof(pre));
memset(vis,0,sizeof(vis));
memset(Q,0,sizeof(Q));
int front=0,rear=1;
pre[s]=s;
vis[s]=1;
Q[front]=s;
while(front<rear){
int p=Q[front++];
for(int i=1;i<=n;i++){
if(r[p][i]&&!vis[i]){
pre[i]=p;
vis[i]=1;
if(i==t) return 1;
Q[rear++]=i;
}
}
}
return 0;
}
int E_k(int s,int t){
int d,i;
flow=0;
while(bfs(s,t)){
d=inf;
for(i=t;i!=s;i=pre[i]){
d=min(d,r[pre[i]][i]);
}
for(i=t;i!=s;i=pre[i]){
r[pre[i]][i]-=d;
r[i][pre[i]]+=d;
}
flow+=d;
}
return flow;
}
int main(){
int m,i,j,a,b,val;
while(~scanf("%d%d",&m,&n)){
memset(r,0,sizeof(r));
for(i=0;i<m;i++){
scanf("%d%d%d",&a,&b,&val);
r[a][b]+=val;
}
printf("%d\n",E_k(1,n));
}
return 0;
}