367. 有效的完全平方数

367. 有效的完全平方数

bool isPerfectSquare(int num){
    long long left=1;
    long long right=num;
    long long middle;
    long long temp=0;
    while(left<=right){
        middle=(left+right)/2;
        if(middle*middle<=num){
            if(middle*middle==num){
                temp=middle;
            }
            left=middle+1;
        }
        else if(middle*middle>num){
            right=middle-1;
        }
    }
    if(temp==0) return false;
    else return temp;
}