public class Solution {
/**
*
* @param x int整型
* @return int整型
*/
public int sqrt (int x) {
if(x<=1) return x;
// write code herei
int begin = 1;
int end = x;
int mid = 0;
while(begin <= end) {
mid = (begin + end) / 2;
if(mid == x/mid) {
return mid;
} else if (mid > x/mid){
end = mid-1;
} else {
begin = mid+1;
}
}
return end;
}
}