2420-find-all-good-indices.adoc

2420. Find All Good Indices

{leetcode}/problems/find-all-good-indices/[LeetCode - 2420. Find All Good Indices ^]

You are given a 0-indexed integer array nums of size n and a positive integer k.

We call an index i in the range k ⇐ i < n - k good if the following conditions are satisfied:

• The k elements that are just before the index i are in non-increasing order.

• The k elements that are just after the index i are in non-decreasing order.

Return an array of all good indices sorted in increasing order.

Example 1:

Input: nums = [2,1,1,1,3,4,1], k = 2
Output: [2,3]
Explanation: There are two good indices in the array:
- Index 2. The subarray [2,1] is in non-increasing order, and the subarray [1,3] is in non-decreasing order.
- Index 3. The subarray [1,1] is in non-increasing order, and the subarray [3,4] is in non-decreasing order.
Note that the index 4 is not good because [4,1] is not non-decreasing.

Example 2:

Input: nums = [2,1,1,2], k = 2
Output: []
Explanation: There are no good indices in this array.

Constraints:

• n == nums.length

• 3 ⇐ n ⇐ 105

• 1 ⇐ nums[i] ⇐ 106

• 1 ⇐ k ⇐ n / 2

思路分析

一刷

link:{sourcedir}/_2420_FindAllGoodIndices.java[role=include]

参考资料