C++创建加权图？

#include<iostream>
#include<vector>
#include <map>

using namespace std;

typedef pair<int, int> PII;

const int INF = 1e9;

int main() {
    int n, m;
    cin >> n >> m;

    vector<map<int, int>> graph(n);

    for (int i = 0; i < m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        graph[u][v] = w;
    }

    // 输出加权图
    for (int u = 0; u < n; u++) {
        for (int v : graph[u]) {
            cout << u << " " << v.first << " " << v.second<< endl;
        }
    }

    return 0;
}