在重载结构体里的“小于”关系时报了个错我之前也写过一个重载结构体里的小于号但是这个没报错怎么一回事呢

在重载结构体里的“小于”关系时报了个错

我之前也写过一个重载结构体里的小于号但是这个没报错

怎么一回事呢？

#include 
#include
#include
#include
using namespace std;
struct edge {
    int from;
    int to;
    int weight;
    edge(int a, int b, int c) : from(a), to(b), weight(c) {}
    bool operator< ( edge n) const {
        return weight < n.weight;
    }
};
vector<int>fathers;
vector<int>height;
priority_queue, greater> q;
int find(int i) {
    if (fathers[i] != i) {
        return find(fathers[i]);
    }
    else {
        return i;
    }
}
void Union(int a, int b) {
    int x = fathers[a];
    int y = fathers[b];
    if (height[x] > height[y]) {
        fathers[y] = x;
    }
    else if (height[x] < height[y]) {
        fathers[x] = y;
    }
    else {
        fathers[x] = y;
        height[x]++;
    }
}
int main() {
    int n;
    while (scanf_s("%d", &n)) {
        if (n == 0) {
            break;
        }
        else {
            for (int i = 0; i < n; i++) {
                fathers[i] = i;
                height[i] = 0;
            }
            for (int i = 0; i < n * (n - 1) / 2; i++) {
                int b, c, d;
                cin >> b >> c >> d;
                q.push(edge(b, c, d));
            }
            int s = 0;
            while (q.size() > 1) {
                if (find(q.top().from) != find(q.top().to)) {
                    Union(q.top().from, q.top().to);
                    s += q.top().weight;
                    q.pop();
                }
                else {
                    q.pop();
                }
            }
            cout << s << endl;
        }
    }
}
// 64 位输出请用 printf("%lld") 

这个警告的意思是，你只重载了<，没有重载>，你要整个一套都重载才行