LeetCode in Kotlin

846. Hand of Straights

Medium

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 ith 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/

Solution

class Solution {
    fun isNStraightHand(hand: IntArray, groupSize: Int): Boolean {
        val len = hand.size
        if (len % groupSize != 0) {
            return false
        }
        hand.sort()
        val map: MutableMap<Int, Int> = HashMap()
        for (num in hand) {
            var cnt = map.getOrDefault(num, 0)
            map[num] = ++cnt
        }
        for (num in hand) {
            var cnt = map[num]!!
            if (cnt <= 0) {
                continue
            }
            map[num] = --cnt
            var loop = 1
            while (loop < groupSize) {
                var curCnt = map.getOrDefault(num + loop, 0)
                if (curCnt <= 0) {
                    return false
                }
                map[num + loop] = --curCnt
                ++loop
            }
        }
        return true
    }
}

This site is open source. Improve this page.