Cod sursa(job #2385145)

Utilizator Constantin.Dragancea Constantin Constantin. Data 21 martie 2019 17:47:38
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.26 kb
#include <bits/stdc++.h>
using namespace std;

#define N 1005
int n, m, c[N][N], maxflow, pr[N];
bool viz[N];
queue <int> Q;
vector <int> v[N];

bool bfs(){
    for (int i=1; i<=n; i++) viz[i] = 0;
    Q.push(1); viz[1] = 1;
    while (!Q.empty()){
        int nod = Q.front();
        Q.pop();
        if (nod == n) continue;
        for (auto it: v[nod]){
            if (viz[it] || !c[nod][it]) continue;
            pr[it] = nod;
            viz[it] = 1;
            Q.push(it);
        }
    }
    return viz[n];
}

int main(){
    ifstream cin ("maxflow.in");
    ofstream cout ("maxflow.out");
    cin >> n >> m;
    for (int i=1, x, y, z; i<=m; i++){
        cin >> x >> y >> z;
        v[x].push_back(y);
        v[y].push_back(x);
        c[x][y] += z;
    }
    while (bfs()){
        for (auto it: v[n]){
            if (!viz[it] || !c[it][n]) continue;
            int flow = 1e9;
            for (int nod = n; nod != 1; nod = pr[nod])
                flow = min(flow, c[pr[nod]][nod]);
            for (int nod = n; nod != 1; nod = pr[nod]){
                c[pr[nod]][nod] -= flow;
                c[nod][pr[nod]] += flow;
            }

            maxflow += flow;
        }
    }
    cout << maxflow;
    return 0;
}