Cod sursa(job #3036543)

Utilizator RalucaioneteRalucaIonete Ralucaionete Data 24 martie 2023 15:53:08
Problema Flux maxim Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.66 kb
///Flux maxim (infoarena)

#include <fstream>
#include <algorithm>
#include <queue>
#include <cmath>
using namespace std;

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

const int N=1e3;
const int INF=2e9;

vector<int>v[N+1];

int flux[N+1][N+1];
int t[N+1];
bool viz[N+1];

int n;

bool bfs(int p)
{
    for(int i=1;i<=n;i++)
        viz[i]=false;

    queue<int>q;
    q.push(p);

    viz[p]=true;
    while(!q.empty())
    {
        int p=q.front();
        q.pop();
        if(p==n)
            return true;
        for(auto i:v[p])
        {
            if(!viz[i] && flux[p][i]>0)
            {
                q.push(i);
                t[i]=p;
                viz[i]=true;
            }
        }
    }
    return false;
}

int main()
{
    int m, i, j, mini=INF, x, y, c;
    long long maxi=0;
    cin >> n >> m;

    for(i=1;i<=m;i++)
    {
        cin >> x >> y >> c;
        flux[x][y]=c;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    while(bfs(1))
    {
        for(auto i:v[n])
        {
            if(!viz[i] || flux[i][n]<=0)
                continue;

            mini=INF;
            t[n]=i;
            x=n;

            while(x!=1)
            {
                mini=min(mini,flux[t[x]][x]);
                x=t[x];
            }

            if(mini==0)
                continue;
            maxi+= mini;

            x=n;
            while(x!=1)
            {
                flux[x][t[x]]=flux[x][t[x]]+mini;
                flux[t[x]][x]=flux[t[x]][x]-mini;
                x=t[x];
            }
        }
    }
    cout<<maxi;
    return 0;
}