#1673 - Find the Most Competitive Subsequence

Problem Description

Given an integer array nums and a positive integer k, return the most competitive subsequence of nums of size k.

An array's subsequence is a resulting sequence obtained by erasing some (possibly zero) elements from the array.

We define that a subsequence a is more competitive than a subsequence b (of the same length) if in the first position where a and b differ, subsequence a has a number less than the corresponding number in b. For example, [1,3,4] is more competitive than [1,3,5] because the first position they differ is at the final number, and 4 is less than 5.

Solution

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {number[]}
 */
var mostCompetitive = function(nums, k) {
  const result = [];
  const n = nums.length;

  for (let i = 0; i < n; i++) {
    while (result.length && result[result.length - 1] > nums[i] && result.length + n - i > k) {
      result.pop();
    }
    if (result.length < k) {
      result.push(nums[i]);
    }
  }

  return result;
};