#2962 - Count Subarrays Where Max Element Appears at Least K Times

Medium • View on LeetCode • View on GitHub

Problem Description

You are given an integer array nums and a positive integer k.

Return the number of subarrays where the maximum element of nums appears at least k times in that subarray.

A subarray is a contiguous sequence of elements within an array.

Solution

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {number}
 */
var countSubarrays = function(nums, k) {
  const maxNum = Math.max(...nums);
  let maxCount = 0;
  let left = 0;
  let result = 0;

  for (let right = 0; right < nums.length; right++) {
    if (nums[right] === maxNum) maxCount++;
    while (maxCount >= k) {
      result += nums.length - right;
      if (nums[left] === maxNum) maxCount--;
      left++;
    }
  }

  return result;
};