Cod sursa(job #2689836)

Utilizator AvramDanielAvram Daniel AvramDaniel Data 22 decembrie 2020 13:40:25
Problema Flux maxim Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.73 kb
#include<bits/stdc++.h>
using namespace std;

#define N 1001
#define fi first
#define se second
#define INF 110000

int adj[N][N];
int n,m;
pair<int,int> path[N];
vector<int> v[N];

void bfs(){
    queue<int> q;
    for(int i = 1;i <= n; i++){
        path[i] = {0, INF};
    }
    q.push(1);
    path[1] = {-1, INF};
    while(!q.empty() && !path[n].fi){
        int curr = q.front();
        q.pop();
        for(auto j: v[curr]){
            if(adj[curr][j]){
                if(!path[j].fi){
                    path[j].fi = curr;
                    path[j].se = min(path[curr].se, adj[curr][j]);
                    q.push(j);
                }
            }
        }
    }
}

int maxflow(){
    int ans = 0;
    while(true){
        bfs();
        if(path[n].fi == 0)
            return ans;
        else{
                for(auto pred: v[n]){
                    int curr = n;
                    path[n].fi = pred;
                    if(min(path[pred].se, adj[pred][n])){
                        int flow = min(path[pred].se, adj[pred][n]);
                        while(path[curr].fi != -1){
                            adj[path[curr].fi][curr] -= flow;
                            adj[curr][path[curr].fi] += flow;
                            curr = path[curr].fi;
                        }
                        ans += flow;
                    }

                }

        }


    }
}


int main(){

    ifstream cin("maxflow.in");
    ofstream cout("maxflow.out");


    cin>>n>>m;
    for(int i = 0;i<m;i++){
        int a,b,c;
        cin>>a>>b>>c;
        adj[a][b] = c;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    cout<<maxflow();

    return 0;
}