P1955 [NOI2015]程序自动分析 离散化+并查集

题目链接 https://www.luogu.com.cn/problem/P1955

AC代码

#include<iostream>
#include <algorithm>
#include<cstdio>
using namespace std;
typedef long long ll;

const int N = 1e6 + 5;
int a[N][3];
int b[N + N];
int par[N+N];
int rank[N +N];
void init(int n)
{
    for (int i = 0; i < n; i++)
    {
        par[i] = i;
        rank[i] = 0;
    }
}
int find(int x)
{
    if (par[x] == x)
    {
        return x;
    }else return par[x] = find(par[x]);
}

void unite(int x, int y)
{
    x = find(x);
    y = find(y);
    if (x == y) return;
    if (rank[x] < rank[y])
    {
        par[x] = y;
    }
    else {
        par[y] = x;
        if (rank[x] == rank[y]) rank[x]++;
    }
}
bool same(int x, int y)
{
    return find(x) == find(y);
}
int main()
{

    ios::sync_with_stdio(false);cin.tie(NULL);
    int t;
    cin >> t;
    while (t--)
    {
        int n;
        int j = 0;

        cin >> n;
        string s = "YES";
        for (int i = 0; i < n; i++)
        {
            cin >> a[i][0] >> a[i][1] >> a[i][2];
            b[j++] = a[i][0];
            b[j++] = a[i][1];
        }
        sort(b, b + j);
        //debug
        int size = unique(b, b + j) - b;
        for (int i = 0; i < n; i++)
        {
            a[i][0] = lower_bound(b, b + size, a[i][0]) - b;
            a[i][1] = lower_bound(b, b + size, a[i][1]) - b;
        }
        init(N+N);
        for (int i = 0; i < n; i++)
        {
            if (a[i][2] == 1) unite(a[i][0],a[i][1]);

        }
        for (int i = 0; i < n; i++)
        {
            if (a[i][2] == 0)
            {

                if (same(a[i][0], a[i][1]))
                    {
                        //debug
                        s = "NO";
                        break;
                    }
            }
        }
        cout << s<< endl;
    }
}