Cod sursa(job #2907709)

Utilizator mateicosCostescu Matei mateicos Data 31 mai 2022 11:54:53
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.45 kb
#include <cstdio>
#include <vector>
#include <set>
using namespace std;

#define MAX_N 50000
#define INF 1e9

struct Edge
{
    int node, cost;
};

int noNodes, noEdges;
vector<Edge> graph[MAX_N];

int dist[MAX_N];

struct HeapCmp
{
    bool operator()(int a, int b)
    {
        return dist[a] < dist[b] || (dist[a] == dist[b] && a < b);
    }
};
set<int, HeapCmp> heap;

void dijkstra(int node)
{
    int i, top;
    set<int>::iterator it;

    for (i = 0; i < noNodes; ++i)
        dist[i] = INF;

    heap.insert({node, 0});
    dist[node] = 0;

    while (!heap.empty())
    {
        top = *heap.begin();
        heap.erase(heap.begin());

        for (Edge edge : graph[top])
            if (dist[edge.node] > edge.cost + dist[top])
            {
                it = heap.find(edge.node);
                if (it != heap.end())
                    heap.erase(it);

                dist[edge.node] = edge.cost + dist[top];
                heap.insert(edge.node);
            }
    }
}

int main()
{
    freopen("dijkstra.in", "r", stdin);
    freopen("dijkstra.out", "w", stdout);

    int i, x, y, c;

    scanf("%d%d", &noNodes, &noEdges);
    for (i = 0; i < noEdges; ++i)
    {
        scanf("%d%d%d", &x, &y, &c);
        --x, --y;

        graph[x].push_back({y, c});
    }

    dijkstra(0);

    for (i = 1; i < noNodes; ++i)
        printf("%d ", dist[i] == INF ? 0 : dist[i]);
    return 0;
}