Cod sursa(job #2391452)

Utilizator Constantin.Dragancea Constantin Constantin. Data 28 martie 2019 21:12:38
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.34 kb
#include <bits/stdc++.h>
using namespace std;

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

bool bfs(int s, int t){
    for (int i=1; i<=n; i++) viz[i] = 0;
    viz[s] = 1; Q.push(s);
    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;
            viz[it] = 1; Q.push(it); p[it] = nod;
        }
    }
    return viz[t];
}

int EdmondsKarp(int s, int t){
    int maxflow = 0;
    while (bfs(s, t)){
        for (auto it: v[n]){
            if (!viz[it] || !c[it][n]) continue;
            int flow = 1e9;
            p[n] = it;
            for (int nod = t; nod != s; nod = p[nod])
                flow = min(flow, c[p[nod]][nod]);
            for (int nod = t; nod != s; nod = p[nod]){
                c[p[nod]][nod] -= flow;
                c[nod][p[nod]] += flow;
            }
            maxflow += flow;
        }
    }
    return maxflow;
}

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;
    }
    cout << EdmondsKarp(1, n);
    return 0;
}