#2744 - Find Maximum Number of String Pairs

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Array String Hash Table Simulation

Problem Description

You are given a 0-indexed array words consisting of distinct strings.

The string words[i] can be paired with the string words[j] if:

The string words[i] is equal to the reversed string of words[j].
0 <= i < j < words.length.

Return the maximum number of pairs that can be formed from the array words.

Note that each string can belong in at most one pair.

Solution

/**
 * @param {string[]} words
 * @return {number}
 */
var maximumNumberOfStringPairs = function(words) {
  const set = new Set();
  let result = 0;

  for (const word of words) {
    const reversed = word[1] + word[0];
    if (set.has(reversed)) {
      result++;
      set.delete(reversed);
    } else {
      set.add(word);
    }
  }

  return result;
};