output-contest-matches.js

/**
 * Output Contest Matches
 *
 * During the NBA playoffs, we always arrange the rather strong team to play with the rather weak team,
 * like make the rank 1 team play with the rank nth team, which is a good strategy to make the contest more
 * interesting. Now, you're given n teams, you need to output their final contest matches in the form of a string.
 *
 * The n teams are given in the form of positive integers from 1 to n, which represents their initial rank.
 * (Rank 1 is the strongest team and Rank n is the weakest team.) We'll use parentheses('(', ')') and commas(',')
 * to represent the contest team pairing - parentheses('(' , ')') for pairing and commas(',') for partition.
 * During the pairing process in each round, you always need to follow the strategy of making the rather strong
 * one pair with the rather weak one.
 *
 * Example 1:
 *
 * Input: 2
 * Output: (1,2)
 *
 * Explanation:
 * Initially, we have the team 1 and the team 2, placed like: 1,2.
 * Then we pair the team (1,2) together with '(', ')' and ',', which is the final answer.
 *
 * Example 2:
 *
 * Input: 4
 * Output: ((1,4),(2,3))
 *
 * Explanation:
 * In the first round, we pair the team 1 and 4, the team 2 and 3 together, as we need to make the strong team and
 * weak team together.
 *
 * And we got (1,4),(2,3).
 *
 * In the second round, the winners of (1,4) and (2,3) need to play again to generate the final winner, so you need
 * to add the paratheses outside them.
 *
 * And we got the final answer ((1,4),(2,3)).
 *
 * Example 3:
 *
 * Input: 8
 * Output: (((1,8),(4,5)),((2,7),(3,6)))
 *
 * Explanation:
 * First round: (1,8),(2,7),(3,6),(4,5)
 * Second round: ((1,8),(4,5)),((2,7),(3,6))
 * Third round: (((1,8),(4,5)),((2,7),(3,6)))
 *
 * Since the third round will generate the final winner, you need to output the answer (((1,8),(4,5)),((2,7),(3,6))).
 *
 * Note:
 *
 * - The n is in range [2, 212].
 * - We ensure that the input n can be converted into the form 2k, where k is a positive integer.
 */

/**
 * @param {number} n
 * @return {string}
 */
const findContestMatch = n => {
  let pairs = Array.from({ length: n }, (v, k) => k + 1);

  while (pairs.length > 1) {
    const temp = [];

    for (let i = 0, j = pairs.length - 1; i < j; i++, j--) {
      temp.push('(' + pairs[i] + ',' + pairs[j] + ')');
    }

    pairs = temp;
  }

  return pairs[0];
};

export { findContestMatch };