Cod sursa(job #2254416)

Utilizator AlexGanasideAlex Ganaside AlexGanaside Data 5 octombrie 2018 12:21:24
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.37 kb
#include <iostream>
#include <vector>
#include <queue>

using namespace std;

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

class mycomparison
{
public:
    bool operator() (const pair<int, int> &lhs, const pair<int, int> &rhs) const
    {
        return lhs.second > rhs.second;
    }
};

const int MAX = 50005, INF = 2e6;
int n, m, d[MAX];
priority_queue<pair<int, int>, vector<pair<int, int> >, mycomparison> pq;
vector<pair<int, int> > gr[MAX];

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;
}