题解 | #求平方根#

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