#include <iostream>
#include <cmath>
using namespace std;

bool isSquare(int num) {
    int i = ___①___;
    int bound = ___②___;
    for (; i <= bound; ++i) {
        if (___③___) return ___④___;
    }
    return ___⑤___;
}

②处应填（ ）。

{{ select(1) }}

• (int)floor(sqrt(num))-1
• (int)floor(sqrt(num))
• floor(sqrt(num/2))-1
• floor(sqrt(num/2))