- Difficulty: Medium
- Tags: LeetCode, Medium, Array, leetcode-2012, O(n), Prefix Sum
Problem
You are given a 0-indexed integer array nums
. For each index i
(1 <= i <= nums.length - 2
) the beauty of nums[i]
equals:
2
, ifnums[j] < nums[i] < nums[k]
, for all0 <= j < i
and for alli < k <= nums.length - 1
.1
, ifnums[i - 1] < nums[i] < nums[i + 1]
, and the previous condition is not satisfied.0
, if none of the previous conditions holds.
Return the sum of beauty of all nums[i]
where 1 <= i <= nums.length - 2
.
Example 1:
Input: nums = [1,2,3] Output: 2 Explanation: For each index i in the range 1 <= i <= 1: - The beauty of nums[1] equals 2.
Example 2:
Input: nums = [2,4,6,4] Output: 1 Explanation: For each index i in the range 1 <= i <= 2: - The beauty of nums[1] equals 1. - The beauty of nums[2] equals 0.
Example 3:
Input: nums = [3,2,1] Output: 0 Explanation: For each index i in the range 1 <= i <= 1: - The beauty of nums[1] equals 0.
Constraints:
3 <= nums.length <= 105
1 <= nums[i] <= 105