/*
 * @lc app=leetcode id=69 lang=java
 *
 * [69] Sqrt(x)
 */

// @lc code=start
class Solution {
    public int mySqrt(int x) {
        long l = 0, r = x+(long)1, m;
        while(r - l > 1) {
            m = l + (r-l)/2;
            if(m*m <= x) {
                l = m;
            } else {
                r = m;
            }
        }
        return (int)l;
    }
}
// @lc code=end