1422. Divide Array In Sets Of K Consecutive Numbers¶

Difficulty: Medium

1422. Divide Array in Sets of K Consecutive Numbers

Medium

Given an array of integers nums and a positive integer k, check whether it is possible to divide this array into sets of k consecutive numbers.

Return true if it is possible. Otherwise, return false.

Example 1:

Input: nums = [1,2,3,3,4,4,5,6], k = 4
Output: true
Explanation: Array can be divided into [1,2,3,4] and [3,4,5,6].

Example 2:

Input: nums = [3,2,1,2,3,4,3,4,5,9,10,11], k = 3
Output: true
Explanation: Array can be divided into [1,2,3] , [2,3,4] , [3,4,5] and [9,10,11].

Example 3:

Input: nums = [1,2,3,4], k = 3
Output: false
Explanation: Each array should be divided in subarrays of size 3.

Constraints:

1 <= k <= nums.length <= 10⁵
1 <= nums[i] <= 10⁹

Note: This question is the same as 846: https://leetcode.com/problems/hand-of-straights/

Solution¶

class Solution {
    public boolean isPossibleDivide(int[] nums, int k) {
        int n = nums.length;
        if (n % k != 0)
            return false;
        HashMap<Integer, Integer> map = new HashMap<>();
        TreeSet<Integer> set = new TreeSet<>();
        for (int ele : nums) {
            set.add(ele);
            map.put(ele, map.getOrDefault(ele, 0) + 1);
        }
        while (map.size() > 0) {
            int current = set.first();
            for (int i = 0; i < k; i++) {
                if (!map.containsKey(current))
                    return false;
                else {
                    map.put(current, map.getOrDefault(current, 0) -1);
                    if (map.getOrDefault(current, 0) == 0) {
                        map.remove(current);
                        set.remove(current);
                    }
                }
                current++;
            }
        }
        return true;
    }
}

Complexity Analysis¶

Time Complexity: O(?)
Space Complexity: O(?)

Approach¶

Detailed explanation of the approach will be added here