69. Sqrt(x)

Implement int sqrt(int x).Compute and return the square root of x, where x is guaranteed to be a non-negative integer.Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned.Example 1:Input: 4Output: 2Example 2:Input: 8Output: 2Explanation: The square root of 8 is 2.82842…, and since the decimal part is truncated, 2 is returned.难度：easy题目：实现sqrt.计算并返回x的开方，x保证非负整。由于返回的类型是整数，十进制数只返回整数部分。Runtime: 22 ms, faster than 30.19% of Java online submissions for Sqrt(x).Memory Usage: 27 MB, less than 99.23% of Java online submissions for Sqrt(x).class Solution { public int mySqrt(int x) { if (0 == x) { return x; } int left = 1, right = x, mid = 0, lastMid = 0; while (left <= right) { mid = left + (right - left) / 2; if (mid > x / mid) { right = mid - 1; } else { left = mid + 1; lastMid = mid; } } return lastMid; }}