910. Smallest Range II.md

910. Smallest Range II

https://leetcode.com/problems/smallest-range-ii/solution/

Given an array A of integers, for each integer A[i] we need to choose either x = -K or x = K, and add x to A[i] **(only once)**.

After this process, we have some array B.

Return the smallest possible difference between the maximum value of B and the minimum value of B.

Example 1:

Input: A = [1], K = 0
Output: 0
Explanation: B = [1]

Example 2:

Input: A = [0,10], K = 2
Output: 6
Explanation: B = [2,8]

Example 3:

Input: A = [1,3,6], K = 3
Output: 3
Explanation: B = [4,6,3]

代码

class Solution(object):
    def smallestRangeII(self, A, K):
        n = len(A)
        A.sort()
        res = A[n-1] - A[0]
        minVal, maxVal = A[0], A[n - 1]
        
        for i in range(n-1):
            a, b = A[i], A[i+1]
            high, low = max(a+K, maxVal-K), min(minVal+K, b-K)
            res = min(res, high - low)
        
        return res