Cod sursa(job #2302850)

Utilizator iarinatudorTudor Iarina Maria iarinatudor Data 15 decembrie 2018 10:52:45
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.31 kb
#include <iostream>
#include <fstream>
#include <climits>
#include <queue>
#include <vector>

using namespace std;
ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");
int dp[50005],ok[50005], cnt[50005],n,m;
vector< pair<int, int> >G[50005];
queue <int> Q;
void citire()
{
    fin>>n>>m;
    for(int i=1; i<=m; i++)
    {
        int x,y,c;
        fin>>x>>y>>c;
        G[x].push_back({y,c});
    }
    for(int i=2; i<=n; i++)
        dp[i]=INT_MAX/2;
}
int neg=0;
void bellman()
{
    dp[1]=0;
    Q.push(1);
    ok[1]=1;
    cnt[1]++;
    while(!Q.empty()&&neg==0)
    {
        int x=Q.front();
        Q.pop();
        ok[x]=0;
        for(auto &v:G[x])
        {
            int y=v.first;
            int cost=v.second;
            if(dp[y]>dp[x]+cost)
            {
                dp[y]=dp[x]+cost;
                if(ok[y]==0)
                {
                    Q.push(y);
                    ok[y]=1;
                    cnt[y]++;
                    if(cnt[y]>n)
                        neg=1;
                }
            }
        }
    }
}
void afish()
{   if(neg==0)
    for(int i=2; i<=n; i++)
        fout<<dp[i]<<" ";
    else
        fout<<"Ciclu negativ!";
}
int main()
{
    citire();
    bellman();
    afish();
    return 0;
}