淘天 4.10 笔试

是不是我审题的问题，第一题暴力只能过0.09，40分钟死磕第三题只过了0.06，第三题到底该怎么做啊

我好像是这么写的，没法调试，也没有记录

import java.util.*;


public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int m = scan.nextInt();
        UF uf = new UF(n);
        int u,v;
        StringBuilder ans = new StringBuilder();
        for (int i = 0; i < m; i++) {
            u = scan.nextInt();
            v = scan.nextInt();
            if(uf.union(u,v)) ans.append("Yes");
            else ans.append("No");
            ans.append('\n');
        }
        System.out.println(ans);
    }


}
class UF {
    private int count;
    private int[] parent;
    private int[] size;
    Set<Long> set;//记录重边
    boolean[] dup;//记录重边集合
    boolean[]circle;//记录有环的集合
    public UF(int n) {
        this.count = n;
        parent = new int[n];
        size = new int[n];
        circle = new boolean[n];
        dup = new boolean[n];
        for (int i = 0; i < n; i++) {
            parent[i] = i;
            size[i] = 1;
        }
    }


    public boolean union(int p, int q) {
        int rootP = find(p);
        int rootQ = find(q);
        boolean d = set.contains(pair(p,q))||set.contains(pair(q,p))||p ==q;//重边或者自环就不能是
        set.add(pair(p,q));
        set.add(pair(q,p));
        dup[rootP] = d;
        dup[rootQ] = d;
        if (rootP == rootQ) {
            circle[rootP] = true;
            return !dup[rootP];
        }
        // 平衡性优化
        if (size[rootP] < size[rootQ]) {
            parent[rootP] = rootQ;
            size[rootQ] += size[rootP];
        } else {
            parent[rootQ] = rootP;
            size[rootP] += size[rootQ];
        }
        return (circle[rootP]||circle[rootQ])&&!(dup[rootP]||dup[rootQ]);
    }
    private int find(int x) {
        if (parent[x] != x) {
            parent[x] = find(parent[x]);
        }
        return parent[x];
    }
    private long pair(int x,int y){
        return ((long)x<<32)+y;
    }




}