LintCode:x的平方根

LintCode:x的平方根

二分法

Python

class Solution:
    """ @param x: An integer @return: The sqrt of x """
    def sqrt(self, x):
        # write your code here
        m = x
        while m * m != x:
            while m * m > x:
                m = m / 2
                n = 2 * m + 1
            while m * m < x:
                if m * m  <= x and (m + 1) * (m + 1) >= x:
                    if(m + 1) * (m + 1) == x:
                        return m + 1
                    else:
                        return m
                m = (n + m) / 2
        return m

Java

class Solution {
    /** * @param x: An integer * @return: The sqrt of x */
    public int sqrt(int x) {
        // write your code here
        long m = x;
        while(m * m  != x){
            while(m * m > x){
                m = m / 2 + 1;
            }
            long n = 2 * m;
            while(m * m < x){
                if (m * m <= x && (m + 1) * (m + 1) >= x){
                    if((m+1) * (m+1) == x){
                        return (int)m+1;
                    }
                    else{
                        return (int)m;
                    }
                }
                m = (m + n) / 2;
            }
        }
        return (int) m;

    }
}