离散化 + 并查集

#include <iostream>
#include <cstdio>
#include <unordered_map>
using namespace std;
const int N = 2E6 + 10;
int n, id;
unordered_map<int, int> mp;
struct node{
    int x, y, e;  
}q[N];
int parent[N];
int get(int x){
    if(mp.count(x) == 0)    mp[x] = ++ id;
    return mp[x];
}
int find(int x){
    if(parent[x] == x)  return x;
    return parent[x] = find(parent[x]);
}
int main(){
    int T;  cin >> T;
    while(T -- ){
        id = 0;
        cin >> n;
        mp.clear();
        for(int i = 0; i < n; i ++ ){
            int x, y, e;    scanf("%d%d%d", &x, &y, &e);
            q[i] = {get(x), get(y), e};     
        }
        for(int i = 0; i < N; i ++ )   parent[i] = i;
        for(int i = 0; i < n; i ++ ){
            if(q[i].e == 1)     parent[find(q[i].x)] = find(q[i].y); 
        }
        bool res = true;
        for(int i = 0; i < n; i ++ ){
            if(q[i].e == 0){
                int px = find(q[i].x), py = find(q[i].y);
                if(px == py){
                    res = false;
                    break;
                }
            }
        }
        if(res) cout << "YES" << endl;
        else    cout << "NO" << endl;
    }
    return 0;
}