LeetCode – Longest Mountain in Array

Link: https://leetcode.com/problems/longest-mountain-in-array/

Solution 1:

• find peak
• go left to find the increasing start index
• go right to find the decreasing end index
• calculate mountain length
• if the current mountain length is bigger than previous max, replace max

/**
 * @param {number[]} arr
 * @return {number}
 */
var longestMountain = function(arr) {
    var max = 0;
    
    for(var i = 1; i < arr.length - 1; i++)
    {
        if (arr[i - 1] < arr[i] && arr[i] > arr[i + 1])
        {
            var l = i - 1;
            var r = i + 1;

            while(arr[l - 1] < arr[l])
                l--;

            while(arr[r] > arr[r+1])
                r++;

            var newMax = r - l + 1;

            if (newMax > max)
                max = newMax;
  
        }
    }

    return max;
};