Przejdź do treści

Dijkstra

Opis problemu

Implementacja

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
#include <iostream>
#include <vector>
#include <queue>
#include <climits>

using namespace std;

struct edge {
    int from;
    int to;
    int distance;

    edge(int from, int to, int distance) {
        this->from = from;
        this->to = to;
        this->distance = distance;
    }
};

void dijkstra(vector<vector<edge> > &graph, vector<int> &distances, int node) {
    queue<edge> edges;

    distances = vector<int>(graph.size(), INT_MAX);
    distances[node] = 0;

    for (int i = 0; i < graph[node].size(); i++) {
        edges.push(graph[node][i]);
    }

    while (!edges.empty()) {
        edge current = edges.front();
        edges.pop();

        int newDistance = distances[current.from] + current.distance;

        if (newDistance >= distances[current.to]) {
            continue;
        }

        distances[current.to] = newDistance;

        for (int i = 0; i < graph[current.to].size(); i++) {
            edges.push(graph[current.to][i]);
        }
    }
}

int main() {
    vector<vector<edge> > graph = {
        {edge(0, 1, 5), edge(0, 6, 5)}, 
        {edge(1, 0, 5), edge(1, 6, 5), edge(1, 3, 3), edge(1, 2, 3)},
        {edge(2, 1, 3), edge(2, 3, 1)},
        {edge(3, 2, 1), edge(3, 1, 3), edge(3, 6, 3), edge(3, 4, 5), edge(3, 5, 4)},
        {edge(4, 3, 5), edge(4, 5, 2)},
        {edge(5, 4, 2), edge(5, 3, 4), edge(5, 6, 5)},
        {edge(6, 0, 5), edge(6, 1, 5), edge(6, 3, 3), edge(6, 5, 5)},
    };

    vector<int> distances;

    dijkstra(graph, distances, 0);

    for(int dist : distances) {
        cout << dist << " ";
    }

    cout << endl;

    return 0;
}

Opis implementacji

Przykładowy graf wykorzystany w implementacji

http://graphonline.ru/en/?graph=DZlFqSBPNgdHwNXK