Cod sursa(job #2254418)

Utilizator AlexGanasideAlex Ganaside AlexGanaside Data 5 octombrie 2018 12:23:58
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.32 kb
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>

using namespace std;

ifstream cin("dijkstra.in");
ofstream cout("dijkstra.out");

const int MAX = 50001, INF = 2e6;

class mycomparison
{
public:
  bool operator() (const pair<int, int> &lhs, const pair<int, int> &rhs) const
  {
    return (lhs.second > rhs.second);
  }
};
priority_queue<pair<int, int>, vector<pair<int, int> >, mycomparison> pq;
vector<pair<int, int> > gr[MAX];
int d[MAX], n, m;
void dijkstra(int s) {
    for(int i = 1; i <= n; ++i) {
        d[i] = INF;
    }
    d[s] = 0;
    pq.push({s, 0});
    while(!pq.empty()) {
        int u = pq.top().first;
        int dist = pq.top().second;
        pq.pop();
        if(dist > d[u]) {
            continue;
        }
        for(unsigned i = 0; i < gr[u].size(); ++i) {
            int v = gr[u][i].first;
            int w = gr[u][i].second;
            if(d[v] > d[u] + w) {
                d[v] = d[u] + w;
                pq.push({v, d[v]});
            }
        }
    }
}
int main()
{
    cin >> n >> m;

    for(int i = 1; i <= m; ++i)
    {
        int u, v, w;
        cin >> u >> v >> w;
        gr[u].push_back({v, w});
    }
    dijkstra(1);
    for(int i = 2; i <= n; ++i) {
        cout << d[i] << ' ';
    }
    return 0;
}