HDU 4279 Number （数论,数学）

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
#include <cmath>
using namespace std;
typedef long long ll;
ll solve(ll x) {
if(x < 3) return 0;
ll res = 0;
res = x / 2 - 1 + ((ll)sqrt((long double)x) % 2 ? 0 : -1);
return res;
}
int main() {
ll a, b, t;
scanf("%I64d", &t);
while(t--) {
scanf("%I64d %I64d", &a, &b);
printf("%I64d\n", solve(b) - solve(a - 1));
}
return 0;
}