Cod sursa(job #3206379)

Utilizator Dragu_AndiDragu Andrei Dragu_Andi Data 22 februarie 2024 15:42:54
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.4 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <algorithm>

using namespace std;

const string filename = "dijkstra";
ifstream fin(filename + ".in");
ofstream fout(filename + ".out");

const int maxN = 50005, inf = 0x3f3f3f3f;
int n, m, dist[maxN];
bool used[maxN];
struct heapNode {
    int nod, cost;
    bool operator < (const heapNode &other) const
    {
        return cost > other.cost;
    }
};
vector <heapNode> G[maxN];
priority_queue <heapNode> heap;

void dijkstra(int start)
{
    for(int i = 1; i <= n; i++)
        dist[i] = inf;
    dist[start] = 0;
    heap.push({start, 0});
    while(!heap.empty())
    {
        heapNode curr = heap.top();
        heap.pop();
        if(used[curr.nod])
            continue;
        used[curr.nod] = 1;
        for(heapNode nxt : G[curr.nod])
        {
            if(dist[curr.nod] + nxt.cost < dist[nxt.nod])
            {
                dist[nxt.nod] = dist[curr.nod] + nxt.cost;
                heap.push({nxt.nod, dist[nxt.nod]});
            }
        }
    }
}

int main()
{
    fin >> n >> m;
    for(int x, y, c, i = 1; i <= m; i++)
    {
        fin >> x >> y >> c;
        G[x].push_back({y, c});
    }
    dijkstra(1);
    for(int i = 2; i <= n; i++)
    {
        if(dist[i] == inf)
            dist[i] = 0;
        fout << dist[i] << ' ';
    }
    return 0;
}