Cod sursa(job #1939255)

Utilizator Train1Train1 Train1 Data 25 martie 2017 16:04:39
Problema Flux maxim Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 1.62 kb
#include <iostream>
#include <fstream>
#include <queue>
#define oo 999999999
#define maxN 1002
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");
int n, m, edge[maxN][maxN], viz[maxN], minValue[maxN];
vector <vector <int> > a;
int bfs(int R) {
    queue <int> q;
    q.push(R);
    for(int i = 0; i <= n; i++) {
        viz[i] = 0;
        minValue[i] = oo;
    }
    viz[R] = -1;
    while(q.size()) {
        int k = q.front();
        q.pop();
        for(int i = 0; i < a[k].size(); i++) {
            if(edge[k][a[k][i]] != 0 && viz[a[k][i]] == 0) {
                q.push(a[k][i]);
                viz[a[k][i]] = k;
                minValue[a[k][i]] = min(minValue[k], edge[k][a[k][i]]);
                if(a[k][i] == n) {
                    break;
                }
            }
        }
    }
    return viz[n];
}
int main()
{
    fin>>n>>m;
    int x, y, z;
    a.resize(n + 1);
    for(int i = 1; i <= m; i++) {
        fin>>x>>y>>z;
        edge[x][y] = z;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    int R = 1;
    int maxFlow = 0;
    while(bfs(R)) {
        int p = n;
        int dif = minValue[p];

        while(viz[p] != - 1 ) { // && p != 0
            if(edge[viz[p]][R]==0) {
            edge[viz[p]][R] = minValue[viz[p]];
            a[R].push_back(viz[p]);
            a[viz[p]].push_back(R);
            }
            edge[viz[p]][p] -= dif;
            edge[p][viz[p]] += dif;
            p = viz[p];
        }
        maxFlow += dif;
    }
    fout<<maxFlow;
    fin.close();
    fout.close();
    return 0;
}