这份代码在本题会 RE？

#include<bits/stdc++.h>
#define ll long long
#define all(x) x.begin(),x.end()
#define rep(i,x,y) for(auto i(x);i<=(y);++i)
#define Rep(i,x,y) for(auto i(x);i>=(y);--i)
using std :: cin ; using std::cout;
const int N = 6e5 ;
int n , m , a[N] ; 
struct query {
	int l,r,id; 
}q[N] ;
const int B = 750 ;
bool cmp (query a,query b) {
	if (a.l / B != b.l / B) return a.l < b.l ;
	return (bool)((a.l / B) & 1) ^ (a.r < b.r) ;
}

signed main ( ) {
	std :: ios :: sync_with_stdio (false) , cin.tie(0) , cout.tie(0) ;
	cin >> n >> m ;
	rep (i,1,n) 
		cin >> a[i] ;
	rep (i,1,m) 
		cin >> q[i].l >> q[i].r , q[i].id = i ;
	std :: sort (q + 1 , q + m + 1 , cmp) ;
}