Cod sursa(job #3036479)

Utilizator AndreiBOTOBotocan Andrei AndreiBOTO Data 24 martie 2023 13:36:41
Problema Flux maxim Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.71 kb
#include <iostream>
#include <fstream>
#include <algorithm>
#include <queue>
#include <cmath>

///#include <tryhardmode>
///#include <GODMODE::ON>

using namespace std;

ifstream fin("maxflow.in");
ofstream fout("maxflow.out");

const int NMAX=1e3+5;
const int INF=2e9;

vector<int>v[NMAX];

int flux[NMAX][NMAX];
int t[NMAX];
bool viz[NMAX];

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;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y>>c;
        flux[x][y]=c;
        flux[y][x]=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=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];
            }
        }
    }
    fout<<maxi;
    return 0;
}