1673-find-the-most-competitive-subsequence.js

/**
 * 1673. Find the Most Competitive Subsequence
 * https://leetcode.com/problems/find-the-most-competitive-subsequence/
 * Difficulty: Medium
 *
 * 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.
 */

/**
 * @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;
};