Sqrt(x)

23% Accepted

Implement int sqrt(int x).

Compute and return the square root of x.

Have you met this question in a real interview? Yes
Example
sqrt(3) = 1

sqrt(4) = 2

sqrt(5) = 2

sqrt(10) = 3

Challenge

O(log(x))

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Binary Search Mathematics

public class Solution {
    public int mySqrt(int x) {
        int start = 0;
        int end = x;
        while (start < end - 1) {
            int mid = start + (end - start) / 2;
            if (mid * mid == x) {
                return mid;
            } else if ((long) mid * mid > (long) x) {
                end = mid;
            } else {
                start = mid;
            }
        }

        if ((long) end * end <= (long) x) {
            return end;
        } else {
            return start;
        }
    }
}