Ridge Summits

Easy

Hikers walked along a mountain ridge and recorded the heights of the points on their route, in order, in the array heights. A **summit** is a point strictly higher than both of its neighbours. The first and last points of the route never count as summits, since each has only one neighbour. Return the indices of all summits (0-based) in any order.

Example 1

heights=[3, 7, 5, 6, 6, 2, 9] → [1]

Point 1 (height 7) is higher than both neighbours. Points 3 and 4 have equal height 6, so neither is strictly higher, and point 6 is an end point, which never counts.

Example 2

heights=[9, 4, 1] → []

The only inner point is lower than its left neighbour.

Example 3

heights=[1, 5, 1, 5, 1] → [1, 3]

Constraints

3 ≤ len(heights) ≤ 100
1 ≤ heights[i] ≤ 100

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Topics

Array Enumeration

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Input

heights=[3, 7, 5, 6, 6, 2, 9]

Expected

[1]

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