@feecle6418 @Alex_Wei

rt，建议卡掉 $\Theta(nq)$ 暴力

Generator:

#include<bits/stdc++.h>
using namespace std;
mt19937 rnd(time(0));
signed main() {
	freopen("P4482.in","w",stdout);
	int n=2e5,q=2e5;
	for(int i=1;i<=n;++i) putchar('a');
	printf("\n%d\n",q);
	while(q--) {
		int l=1+(rnd()%100),r=n-(rnd()%100);
		printf("%d %d\n",l,r);
	}
	return 0;
}