Hand of Straights – Mahmoud Ashraf

846. Hand of Straights 🔗

Date: Jun 07, 2024

Tags: hash-map, min-heap, heaps

Description

Alice has some number of cards and she wants to rearrange the cards into groups so that each group is of size groupSize, and consists of groupSize consecutive cards.

Given an integer array hand where hand[i] is the value written on the i^th card and an integer groupSize, return true if she can rearrange the cards, or false otherwise.

Example 1:

          Input: hand = [1,2,3,6,2,3,4,7,8], groupSize = 3
          Output: true
          Explanation: Alice's hand can be rearranged as [1,2,3],[2,3,4],[6,7,8]

Example 2:

          Input: hand = [1,2,3,4,5], groupSize = 4
          Output: false
          Explanation: Alice's hand can not be rearranged into groups of 4.

Constraints:

1 <= hand.length <= 10⁴
0 <= hand[i] <= 10⁹
1 <= groupSize <= hand.length

Note: This question is the same as 1296: https://leetcode.com/problems/divide-array-in-sets-of-k-consecutive-numbers/

With Sorted Array + Hash-Map

function isNStraightHand(hand: number[], groupSize: number): boolean {
  if (hand.length % groupSize !== 0) return false;

  hand.sort((a, b) => a - b);

  const counter: Record<number, number> = {};

  for (const card of hand) {
    counter[card] = (counter[card] || 0) + 1;
  }

  for (const card of hand) {
    if (counter[card] === 0) continue;

    for (let i = 0; i < groupSize; i++) {
      if (!counter[card + i]) return false;
      counter[card + i]--;
    }
  }

  return true;
}

export { isNStraightHand };