Package g0801_0900.s0845_longest_mountain_in_array

Class Solution

java.lang.Object
g0801_0900.s0845_longest_mountain_in_array.Solution
public class Solution extends java.lang.Object
845 - Longest Mountain in Array.

Medium

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 ) with 0 < 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?

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    longestMountain(int[] arr)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • longestMountain

      public int longestMountain(int[] arr)