Sqrt(X)，求平方根，折半查找

算法分析：利用折半查找，降低算法复杂度。前面求x得y次幂，也是将y/2，都是为了降低复杂度。

//折半查找的思想
public class Sqrt
{
	public int sqrt(int x)
	{
		int low = 0;
		int high = x;
		while(low <= high)
		{
			long mid = (low + high)/2;
			if(mid*mid > x)//为了防止mid*mid溢出，将mid定义为long
			{
				high = (int)mid - 1;
			}
			else if(mid*mid < x)
			{
				low = (int)mid + 1;
			}
			else
			{
				return (int)mid;
			}
		}
		return high;
	}
}

 

转载于:https://www.cnblogs.com/masterlibin/p/5780171.html