Cod sursa(job #1051478)

Utilizator paunmatei7FMI Paun Matei paunmatei7 Data 10 decembrie 2013 08:33:44
Problema Flux maxim Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 1.71 kb
#include<stdio.h>
#include<vector>
#include<algorithm>
#include<queue>
#include<string.h>

#define x first
#define y second
#define NMAX 1007
#define INF 100000000

using namespace std;

int Cap[NMAX][NMAX], dad[NMAX], q[NMAX];
int n, Maxflow, m;

vector<int> v[NMAX];

inline bool bfs(){
    int start = 0, avans = 0;
    q[avans++] = 1;
    dad[1] = -2;
    while(avans > start && dad[n] == -1){
        int Nod = q[start++];
        for(int i = 0; i < v[Nod].size(); ++ i)
            if(dad[v[Nod][i]] == -1 && Cap[Nod][v[Nod][i]] > 0){
                q[avans++] = v[Nod][i];
                dad[v[Nod][i]] = Nod;
                if(v[Nod][i] == n)
                    return 1;
            }
    }
    return 0;
}

int main(){
    freopen("maxflow.in", "r", stdin);
    freopen("maxflow.out", "w", stdout);
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= m; ++i){
        int a = 0, b = 0, c = 0;
        scanf("%d %d %d", &a, &b, &c);
        v[a].push_back(b);
        v[b].push_back(a);
        Cap[a][b] += c;
    }
    while(1){
        memset(dad, -1, sizeof(dad));
        bfs();
        if(dad[n] == -1)
            break;
        for(int i = 1; i <= n; ++ i)
            if(Cap[i][n] && dad[i] != -1){
                int Min = INF;
                for(int Nod = i; Nod > 1; Nod = dad[Nod])
                    Min = min(Min, Cap[dad[Nod]][Nod]);
                if (!Min)
                    continue;
                Maxflow += Min;
                for(int Nod = i; Nod > 1; Nod = dad[Nod]){
                    Cap[Nod][dad[Nod]] += Min;
                    Cap[dad[Nod]][Nod] -= Min;
                }
            }
    }
    printf("%d", Maxflow);
    return 0;
}