removeDuplicates.mjs

/**
 * Remove duplicate values from a sequence, preserving the order of the first occurrence of each value.
 *
 * Time Complexity: O(n) — the function iterates through the input sequence once
 * Space Complexity: O(n) — in the worst case, all elements are unique and stored in the Set and output array
 * Optimal Time Complexity: O(n) — must at least visit each element once
 *
 * @param {Array} inputSequence - Sequence to remove duplicates from
 * @returns {Array} New sequence with duplicates removed
 */
export function removeDuplicates(inputSequence) {
  const seen = new Set();
  const uniqueItems = [];

  for (const item of inputSequence) {
    if (!seen.has(item)) {
      seen.add(item);
      uniqueItems.push(item);
    }
  }

  return uniqueItems;
}