非正解，并查集：

#include<iostream>
using namespace std;
int n, m, q, x, y;
int rel[5010];
int find(int a) {
	if (a == rel[a]) return a;
	return rel[a] = find(rel[a]);
}
void join(int a, int b) {
	int p = find(a), q = find(b);
	if (p != q) rel[p] = q;
}
int main() {
	freopen("tea.in", "r", stdin);
	freopen("tea.out", "w", stdout);
	scanf("%d%d%d", &n, &m, &q);
	for (int i = 1; i <= n; ++ i)
	    rel[i] = i;
	while (m --){
	    scanf("%d%d", &x, &y);
		join(x, y);
	}
	while (q --){
	    scanf("%d%d", &x, &y);
		putchar(find(x) == find(y) ? 'Y' : 'N');
		putchar('\n');
	}
	return 0;
}