LeetCode 69. Sqrt(x)

Description

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: 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.

整型“开方”

根据题意，mySqrt(x) = floor(sqrt(x))

Solution

使用二分法进行查找

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func mySqrt(x int) int {
    if x == 0 {
        return 0
    }
    left, right := 1, x/2

    for left < right {
        m := right - (right-left)/2
        if m*m > x {
            right = m - 1
        } else {
            left = m
        }
    }

    return left
}

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