Mai intai trebuie sa te autentifici.
Cod sursa(job #2423973)
Utilizator | Data | 22 mai 2019 13:14:43 | |
---|---|---|---|
Problema | Algoritmul Bellman-Ford | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 1.65 kb |
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define NMAX 1001000
#define INF 1000000
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");
vector <pair<int,int> > graf[NMAX];
int viz[NMAX];
int cost[NMAX];
int frecventa[NMAX];
int n,m;
struct compara
{
bool operator()(int x, int y)
{
return cost[x] > cost[y];
}
};
priority_queue<int, vector<int>, compara> coada;
int dijkstra (int nodStart)
{
cost[nodStart] = 0;
coada.push(nodStart);
viz[nodStart] = 1;
while(!coada.empty())
{
int nodCurent = coada.top();
coada.pop();
viz[nodCurent] = 0;
frecventa[nodCurent]++;
if(frecventa[nodCurent] > m)
{
g<<"Ciclu negativ!\n";
return 0;
}
int lim = graf[nodCurent].size();
for(int i=0; i<lim; i++)
{
int vecin = graf[nodCurent][i].first;
int cos = graf[nodCurent][i].second;
if(cost[nodCurent] + cos < cost[vecin])
{
cost[vecin] = cost[nodCurent] + cos;
if(viz[vecin] == 0)
{
coada.push(vecin);
viz[vecin] = 1;
}
}
}
}
return 1;
}
int main()
{
int x,y,c,i;
f>>n>>m;
for(i=1; i<=m; i++)
{
f>>x>>y>>c;
graf[x].push_back(make_pair(y,c));
}
for(i=1; i<=n; i++)
{
viz[i] = 0;
cost[i] = INF;
}
if(dijkstra(1) == 1)
for(i=2; i<=n; i++) g<<cost[i]<<" ";
return 0;
}