Cod sursa(job #1825780)

Utilizator tudormaximTudor Maxim tudormaxim Data 9 decembrie 2016 17:18:21
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.6 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

ifstream fin ("dijkstra.in");
ofstream fout ("dijkstra.out");

const int maxn = 5e4 + 5;
const int oo = 1 << 29;
vector <pair <int,int> > G[maxn];
int Dist[maxn], n;

class Cmp {
public:
    inline bool operator () (pair <int,int> &x, pair <int,int> &y) {
        return x.second > y.second;
    }
};

void Dijkstra(int source) {
    priority_queue <int, vector < pair <int,int> >, Cmp> Heap;
    vector < pair<int,int> > :: iterator it;
    int i, node, cost;
    for (i = 1; i <= n; i++) {
        Dist[i] = oo;
    }
    Dist[source] = 0;
    Heap.push(make_pair(source, Dist[source]));
    while (!Heap.empty()) {
        node = Heap.top().first;
        cost = Heap.top().second;
        Heap.pop();
        if (Dist[node] != cost) {
            continue;
        }
        for (it = G[node].begin(); it != G[node].end(); it++) {
            if (Dist[it->first] > Dist[node] + it->second) {
                Dist[it->first] = Dist[node] + it->second;
                Heap.push(make_pair(it->first, Dist[it->first]));
            }
        }
    }
}

int main() {
    ios_base :: sync_with_stdio (false);
    int m, i, x, y, c;
    fin >> n >> m;
    for (i = 1; i <= m; i++) {
        fin >> x >> y >> c;
        G[x].push_back(make_pair(y, c));
    }
    Dijkstra(1);
    for (i = 2; i <= n; i++) {
        if (Dist[i] == oo) {
            fout << "0 ";
        } else {
            fout << Dist[i] << " ";
        }
    }
    fin.close();
    fout.close();
    return 0;
}