Cod sursa(job #2305664)

Utilizator andreicoman299Coman Andrei andreicoman299 Data 20 decembrie 2018 20:01:05
Problema Flux maxim Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.22 kb
#include <bits/stdc++.h>
#define MAXN 1000

int n, m, S, D, flux;
std::vector <int> G[1 + MAXN];
int C[1 + MAXN][1 + MAXN];
int father[1 + MAXN];
int q[1 + MAXN], p, u;

inline bool bfs(){
    memset(father, 0, sizeof(father));
    p = 0, u = 1;
    q[0] = S;
    while(p != u){
        int node = q[p++];
        for(auto y:G[node])
            if(!father[y] && C[node][y]) father[y] = node, q[u++] = y;
    }
    return (father[D] != 0);
}

int main(){
    FILE*fi,*fo;
    fi = fopen("maxflow.in","r");
    fo = fopen("maxflow.out","w");

    fscanf(fi,"%d%d", &n, &m);
    for(int i = 1; i <= m; i++){
        int x, y, z;
        fscanf(fi,"%d%d%d", &x, &y, &z);
        G[x].push_back(y);
        G[y].push_back(x);
        C[x][y] += z;
    }

    S = 1, D = n;
    while(bfs())
        for(auto y:G[D])
            if(father[y] && C[y][D]){
                father[D] = y;
                int flow = 1000000000;
                for(int i = D; i != S; i = father[i]) flow = std::min(flow, C[father[i]][i]);
                for(int i = D; i != S; i = father[i]) C[father[i]][i] -= flow, C[i][father[i]] += flow;
                flux += flow;
            }
    fprintf(fo,"%d", flux);
    return 0;
}