2900-longest-unequal-adjacent-groups-subsequence-i.js

/**
 * 2900. Longest Unequal Adjacent Groups Subsequence I
 * https://leetcode.com/problems/longest-unequal-adjacent-groups-subsequence-i/
 * Difficulty: Easy
 *
 * You are given a string array words and a binary array groups both of length n, where words[i]
 * is associated with groups[i].
 *
 * Your task is to select the longest alternating subsequence from words. A subsequence of words
 * is alternating if for any two consecutive strings in the sequence, their corresponding elements
 * in the binary array groups differ. Essentially, you are to choose strings such that adjacent
 * elements have non-matching corresponding bits in the groups array.
 *
 * Formally, you need to find the longest subsequence of an array of indices [0, 1, ..., n - 1]
 * denoted as [i0, i1, ..., ik-1], such that groups[ij] != groups[ij+1] for each 0 <= j < k - 1
 * and then find the words corresponding to these indices.
 *
 * Return the selected subsequence. If there are multiple answers, return any of them.
 *
 * Note: The elements in words are distinct.
 */

/**
 * @param {string[]} words
 * @param {number[]} groups
 * @return {string[]}
 */
var getLongestSubsequence = function(words, groups) {
  const result = [words[0]];
  let lastGroup = groups[0];

  for (let i = 1; i < words.length; i++) {
    if (groups[i] !== lastGroup) {
      result.push(words[i]);
      lastGroup = groups[i];
    }
  }

  return result;
};