Cod sursa(job #2949310)

Utilizator acostin643costin andrei acostin643 Data 30 noiembrie 2022 13:45:09
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.54 kb
#include <fstream>
#include <queue>
#include <vector>
#include <iostream>
#include <limits.h>

using namespace std;

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

const int NMAX = 50000;
typedef pair<int, int> pi;

int in;
bool visited[NMAX + 5];
long long shortest[NMAX + 5];
int N, M;
int a, b, c;
vector <int> g[NMAX + 5];
vector <int> v[NMAX + 5];
priority_queue <pi, vector<pi>, greater<pi>> pq;

void dijkstra(int curr_length, int src)
{
    for(int i = 0; i < g[src].size(); i++)
    {
        if(!visited[g[src][i]])
        {
            if(curr_length + v[src][i] < shortest[g[src][i]])
            {
                shortest[g[src][i]] = curr_length + v[src][i];
                pq.push(make_pair(shortest[g[src][i]], g[src][i]));
            }
        }
    }
}

int main()
{
    fin >> N >> M;

    for(int i = 0; i <= N; i++)
        shortest[i] = INT_MAX;

    for(int i = 1; i <= M; i++)
    {
        fin >> a >> b >> c;

        g[a].push_back(b);
        v[a].push_back(c);

        g[b].push_back(a);
        v[b].push_back(c);
    }

    //prima e lungimea de la sursa, a doua este nodul
    pq.push({0, 1});
    while(!pq.empty())
    {
        visited[pq.top().second] = 1;
        dijkstra(pq.top().first, pq.top().second);
        pq.pop();
        if(!pq.empty())
            while(visited[pq.top().second] == 1)
                pq.pop();
    }

    for(int i = 2; i <= N; i++)
        fout << shortest[i] << " ";

    fin.close();
    fout.close();
    return 0;
}