69. Sqrt(x)

[Tcdian]

69. Sqrt(x)

实现 int sqrt(int x) 函数。

计算并返回 x 的平方根，其中 x 是非负整数。

由于返回类型是整数，结果只保留整数的部分，小数部分将被舍去。

Example 1

Input: 4
Output: 2

Example 2

Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since 
             the decimal part is truncated, 2 is returned.

[Tcdian]

Solution

• JavaScript Solution

/**
 * @param {number} x
 * @return {number}
 */
var mySqrt = function(x) {
    let result;
    let left = 0;
    let right = x;
    while (left <= right) {
        const mid = Math.floor((left + right) / 2);
        if (mid * mid === x) {
            result = mid;
            break;
        } else if (mid * mid < x) {
            result = mid;
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }
    return result;
};