邻接表代码c++语言

以下是C++语言中邻接表的基本代码实现：

#include <iostream>
#include <vector>
#include <utility>
#include <queue>
using namespace std;

const int MAXN = 1005;
const int INF = 0x3f3f3f3f;

vector<pair<int, int>> graph[MAXN]; // 邻接表{from, {to, dis}} （即pair<int, int> = {to, dis}）

struct cmp{
    bool operator()(pair<int, int>& a, pair<int, int>& b) {
        return a.second > b.second; // 以pair中的第二个元素，即edg{Vk, Vm}的大小来判断在堆中的位置
    }
};

int dijkstra(int start, int end) {
    priority_queue<pair<int, int>, vector<pair<int, int>>, cmp> q;
    vector<int> dis(MAXN, INF);
    vector<bool> vis(MAXN, false);
    dis[start] = 0;
    q.push({start, 0});
    while (!q.empty()) {
        int u = q.top().first;
        q.pop();
        if (vis[u]) continue;
        vis[u] = true;
        for (auto& edg : graph[u]) {
            int v = edg.first, w = edg.second;
            if (dis[v] > dis[u] + w) {
                dis[v] = dis[u] + w;
                q.push({v, dis[v]});
            }
        }
    }
    return dis[end];
}

int main() {
    int n, m, s, t;
    cin >> n >> m >> s >> t;
    for (int i = 0; i < m; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        graph[u].push_back({v, w});
        graph[v].push_back({u, w}); // 无向图
    }
    int ans = dijkstra(s, t);
    cout << ans << endl;
    return 0;
}