845. Longest Mountain in Array
Description
You may recall that an array arr
is a mountain array if and only if:
arr.length >= 3
- There exists some index
i
(0-indexed) with0 < i < arr.length - 1
such that:arr[0] < arr[1] < ... < arr[i - 1] < arr[i]
arr[i] > arr[i + 1] > ... > arr[arr.length - 1]
Given an integer array arr
, return the length of the longest subarray, which is a mountain. Return 0
if there is no mountain subarray.
Example 1:
Input: arr = [2,1,4,7,3,2,5] Output: 5 Explanation: The largest mountain is [1,4,7,3,2] which has length 5.
Example 2:
Input: arr = [2,2,2] Output: 0 Explanation: There is no mountain.
Constraints:
1 <= arr.length <= 104
0 <= arr[i] <= 104
Follow up:
- Can you solve it using only one pass?
- Can you solve it in
O(1)
space?
Solutions
Solution 1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 |
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
|
Solution 2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 |
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 |
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 |
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