Cod sursa(job #2484268)

Utilizator iulianarsenoiuArsenoiu Iulian iulianarsenoiu Data 30 octombrie 2019 20:50:43
Problema Algoritmul Bellman-Ford Scor 95
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.21 kb
#include <fstream>
#include <queue>
#include <vector>

using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");
const int INF=0x3f3f3f3f;
queue <int> q;
vector <pair<int,int>> G[50005];
int n,m,x,y,c,i,d[50005],nr[50005];
bool sel[50005];
void Bellmanford()
{
    for(int i=1;i<=n;i++)
        d[i]=INF,sel[i]=false;
    sel[1]=true;
    nr[1]=1;
    q.push(1);
    d[1]=0;
    bool done=false;
    while(!q.empty() && !done)
    {
        x=q.front();
        q.pop();
        sel[x]=false;
        for(auto it : G[x])
        {
            if(nr[it.second]>n)
                done=true;
            else if(d[x]+it.first<d[it.second])
            {
                d[it.second]=d[x]+it.first;
                if(!sel[it.second])
                {
                    q.push(it.second);
                    nr[it.second]++;
                    sel[it.second]=true;
                }
            }
        }
    }
}
int main()
{
    f>>n>>m;
    for(i=1;i<=m;++i)
    {
        f>>x>>y>>c;
        G[x].push_back({c,y});
    }
    Bellmanford();
    if(d[1]<0)
        g<<"Ciclu negativ!"<<'\n';
    else for(i=2;i<=n;i++)
        g<<d[i]<<' ';
    return 0;
}