README_EN.md

846. Hand of Straights

中文文档

Description

Alice has a hand of cards, given as an array of integers.

Now she wants to rearrange the cards into groups so that each group is size W, and consists of W consecutive cards.

Return true if and only if she can.

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

 

Example 1:

Input: hand = [1,2,3,6,2,3,4,7,8], W = 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], W = 4
Output: false
Explanation: Alice's hand can't be rearranged into groups of 4.

 

Constraints:

• 1 <= hand.length <= 10000
• 0 <= hand[i] <= 10^9
• 1 <= W <= hand.length

Solutions

Python3

Java

class Solution {
    public boolean isNStraightHand(int[] hand, int groupSize) { 
        if (hand.length % groupSize != 0) {
            return false;
        }
        TreeMap<Integer, Integer> mp = new TreeMap<>();
        for (int item : hand) {
            mp.put(item, mp.getOrDefault(item, 0) + 1);
        }

        while (mp.size() > 0) {
            int start = mp.firstKey();
            for (int i = start; i < start + groupSize; i++) {
                if (!mp.containsKey(i)) {
                    return false;
                }
                int time = mp.get(i);
                if (time == 1) {
                    mp.remove(i);
                } else {
                    mp.replace(i, time - 1);
                }
            }
        }
        return true;
    }
}

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