Cod sursa(job #2520489)

Utilizator AndreiDeltaBalanici Andrei Daniel AndreiDelta Data 9 ianuarie 2020 14:47:35
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.44 kb
#include <bits/stdc++.h>
#define oo 1e9+1
#define Dim 50001
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");
int N,M,x,y,z,D[Dim],R[Dim];
bool there[Dim];

typedef pair < int,int > pi;

vector < pi > V[Dim];

struct cmp
{
    bool operator () ( int x,int y)
    {
        if( D[x] < D[y] ) return 1;
        else
        if(D[x]==D[y])
        {
            if( x<y ) return 1;
            else return 0;
        }
        else return 0;
    }
};

set < int,cmp > S;

int main()
{
    f>>N>>M;
    for(int i=1;i<=M;i++)
    {
        f>>x>>y>>z;
        V[x].push_back({y,z});
    }
    for(int i=2;i<=N;i++) D[i]=oo;

    D[1]=0;
    there[1]=1;
    S.insert(1);
    int cnt=0;

    while(!S.empty())
    {

        int nod=*S.begin();
        S.erase(S.begin());
        there[nod]=0;

        R[nod]++;
        if( R[nod] == N   )
        {
            g<<"Ciclu negativ!";
            return 0;
        }


        for(unsigned int i=0;i<V[nod].size();i++)
        {
            int  vecin=V[nod][i].first;
            int cost=V[nod][i].second;

            if( D[vecin] > D[nod] + cost )
            {
                if( there[vecin]==1 ) S.erase( S.find(vecin) );
                D[vecin]=D[nod]+cost;

                S.insert(vecin);
                there[vecin]=1;

            }
        }
    }

    for(int i=2;i<=N;i++) g<<D[i]<<" ";

    return 0;
}