题解 | #求平方根#

此处是通过累加去求结果，每次增加一个奇数，获得下一次的平方和。而后将平方和与所给x进行比较。

class Solution {
public:
    /**
     *
     * @param x int整型
     * @return int整型
     */
   int sqrt(int x) {
        if(x<=0) 
        	return 0;  //小于等于0 返回0
        int ans = 1; 
        int num = 1;
        int  i = 3;
        while(num + i <= x){
            num += i;  
            ans++; // 每加一个奇数，ans+1
            i += 2;
        }
        return ans;
    }
};

import java.util.*;


public class Solution {
    /**
     * 
     * @param x int整型 
     * @return int整型
     */
    public int sqrt (int x) {
        // write code here
        if (x == 1 || x == 0)
            return x;
        int left = 0, right = x, mid = 0;
        while (left < right) {
        mid = left + (right - left) / 2;
            if (((mid + 1) > x/(mid + 1)) && (mid <= x / mid))
                return mid;
            else if (mid > x / mid)
                right = mid;
             else
                 left = mid;
            }
        return mid;
    }
}