連結：https://www.luogu.org/problemnew/show/P1551

import java.util.Scanner;
public class Main{
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt(),
            m = in.nextInt(),
            p = in.nextInt();
        UnionFind uf = new
 
 UnionFind(n+1);
        Integer[] arr = uf.arr;
        for (int i = 0; i < m; i++) {
            int a = in.nextInt();
            int b = in.nextInt();
            uf.union(a, b);
        }
        for (int i = 0; i < p; i++) {
            int a = in.nextInt(),
                b = in.nextInt(
 
);
            if (uf.findRoot(arr[a]) == uf.findRoot(arr[b]))
                System.out.println("Yes");
            else System.out.println("No");
        }
}

class UnionFind {
    Integer[] arr;
    public UnionFind(int size) {
        this.arr = new Integer[size];
        for (int i = 1; i <
 
 arr.length; i++)
            arr[i] = new Integer(i);
    }
    public int findRoot(int i) {
        while (i != arr[i]) i = arr[i];
        return i;
    }
    public void union(int a, int b) {
        a = findRoot(a);
        b = findRoot(b);
        arr[a] = b;
    }
}