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Cod sursa(job #931540)
#include<iostream>
#include<vector>
#include<fstream>
#include<queue>
#include<cstring>
using namespace std;
#define INF 100000000
#define MAX 1024
int F[MAX][MAX], C[MAX][MAX];
int search(int n, vector<int> v[], int p[]);
int main(){
int n,m;
ifstream cinr("maxflow.in");
cinr >> n >> m;
vector<int> v[n+1];
int p[n+1];
for(int i=1; i<=n; i++)
for(int j=1; j<=n; j++)
F[i][j]=C[i][j]=0;
for(int i=0; i<m; i++){
int a,b,c;
cinr >> a >> b >> c;
v[a].push_back(b);
F[a][b]+=c; C[a][b]+=c;
v[b].push_back(a);
} cinr.close();
int min=search(n,v,p);
while(p[n]!=0){
int i=n;
while(i!=1){
int r; r=p[i];
C[r][i]-=min;
C[i][r]+=min;
i=r;
}
min=search(n,v,p);
}
int sum=0;
for(int i=1; i<=n; i++){
sum+=F[1][i]-C[1][i];
}
ofstream cour("maxflow.out");
cour << sum;
cour.close();
}
int search(int n, vector<int> v[], int p[]){
bool vis[n+1];
memset(vis,0,sizeof(vis));
for(int i=1; i<=n; i++) p[i]=0;
queue<int> q;
q.push(1); q.push(INF);
int min;
while(!q.empty()){
int r;
r=q.front(); q.pop();
min=q.front(); q.pop();
vis[r]=true;
for(int i=0; i<v[r].size(); i++){
int to;
to=v[r][i];
if(!vis[to] && C[r][to]!=0){
p[to]=r;
if(C[r][to]<min) min=C[r][to];
if(to==n) return min;
q.push(to); q.push(min);
}
}
}
return min;
}