Cod sursa(job #990621)

Utilizator gabrielinelusGabriel-Robert Inelus gabrielinelus Data 28 august 2013 18:49:08
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.44 kb
#include <cstdio>
#include <algorithm>
#include <queue>
#include <vector>
#include <climits>

#define mp make_pair
#define pb push_back

using namespace std;
const int inf=INT_MAX/2;
int n,m,D[50001];

vector< pair <int,int> > lv[50001];
int times_used[ 50001 ],negative;
void make_GRAPH()
{
    scanf("%d%d", &n, &m);
    int a,b,c,i;
    for(i = 1; i <= m; ++i){
        scanf("%d%d%d",&a,&b,&c);
        lv[ a ].pb(mp(b,c));
    }
}

void Bellman_Ford()
{
    vector< pair<int,int> > ::iterator it;
    queue<int> Q;
    int k;
    for(int i = 2; i <= n; ++i)
        D[ i ] = inf;
    Q.push(1);
    while(!Q.empty()&& !negative){
        k = Q.front();Q.pop();
        for(it = lv[k].begin(); it != lv[k].end(); ++it)
            if(D[it->first] > D[k] + it->second)
            {
                D[ it->first ] = D[k] + it->second;
                times_used[ it->first ]++;
                Q.push(it->first);
                if(times_used[ it->first ] > n)negative = 1;
            }
    }
}

void Print()
{
    if(negative == 1)
        printf("Ciclu negativ!\n");
    else{
        for(int i=2; i<=n; ++i)
                if(D[i] != inf)
                        printf("%d ",D[i]);
                else printf("0 ");
    }
}

int main()
{
    freopen( "dijkstra.in", "r", stdin);
    freopen( "dijkstra.out", "w", stdout);

    make_GRAPH();
    Bellman_Ford();

    Print();
    return 0;
}