Given a positive integer num, write a function which returns Trueif num is a perfect square else False.
注意事项
Do not use any built-in library function such as sqrt.
样例
For example:
Given num = 16
Returns True
二分查找
没什么说的，二分查找基本功。
代码语言：javascript复制 bool isPerfectSquare(int num) {
int beg=0;
int end=num;
int mid;
while(beg<=end)
{
mid=beg (end-beg)/2;
if(pow(mid,2)==num)
return true;
else if(pow(mid,2)<num) beg=mid 1;
else end=mid-1;
}
return false;
// write your code here
}
