Cod sursa(job #2126159)

Utilizator antanaAntonia Boca antana Data 9 februarie 2018 11:53:05
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.39 kb
#include <bits/stdc++.h>

using namespace std;

ifstream fi( "dijkstra.in" );
ofstream fo( "dijkstra.out");

const int maxn = 5e4 + 5;
const int inf  = 0x3f3f3f3f;

vector < pair < int, int > > g[maxn];

priority_queue < pair < int, int > > heap;
//priority_queue < pair <int, int>, vector < pair<int, int> >, greater <pair<int, int> > > heap;

int n, m, dist[maxn];

void dijkstra( int start ) {
    int node, d, son, cost;

    heap.push( { 0, start } );
    while (!heap.empty()) {
        node = heap.top().second;
        d = -heap.top().first;

        heap.pop();

        if (d > dist[ node ])
            continue;

        for (int i = 0; i < g[ node ].size(); i++) {
            son = g[ node ][ i ].first;
            cost = g[ node ][ i ].second;

            if (dist[ son ] > d + cost) {
                dist[ son ] = d + cost;
                heap.push( { -dist[ son ], son } );
            }
        }
    }
}

int main()
{
    int x, y, z;

    fi >> n >> m;
    for (int i = 1; i <= m; i++) {
        fi >> x >> y >> z;
        g[ x ].push_back( { y, z } );
    }

    for (int i = 2; i <= n; i++)
        dist[ i ] = inf;
    dist[ 1 ] = 0;

    dijkstra( 1 );

    for (int i = 2; i <= n; i++) {
        if (dist[ i ] == inf) {
            fo << 0 << " ";
        }
        else
            fo << dist[ i ] << " ";
    }

    return 0;
}