[LeetCode] 1296. Divide Array in Sets of K Consecutive Numbers

Given an array of integers nums and a positive integer k, find whether it's possible to divide this array into sets of k consecutive numbers
Return True if its 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 = [3,3,2,2,1,1], k = 3
Output: true

Example 4:

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

Constraints:

• 1 <= nums.length <= 10^5
• 1 <= nums[i] <= 10^9
• 1 <= k <= nums.length

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

划分数组为连续数字的集合。

题意跟846题真的是一模一样，那么思路也就请参见846题吧。

时间O(nlogn)

空间O(n)

Java实现

class Solution {
    public boolean isPossibleDivide(int[] nums, int k) {
        // corner case
        if (nums.length % k != 0) {
            return false;
        }

        // normal case
        HashMap<Integer, Integer> map = new HashMap<>();
        for (int num : nums) {
            map.put(num, map.getOrDefault(num, 0) + 1);
        }
        Arrays.sort(nums);
        for (int i = 0; i < nums.length; i++) {
            if (map.get(nums[i]) == 0) {
                continue;
            }
            int cur = nums[i];
            int end = nums[i] + k;
            while (cur < end) {
                int count = map.getOrDefault(cur, 0);
                if (count == 0) {
                    return false;
                }
                map.put(cur, map.get(cur) - 1);
                cur++;
            }
        }
        return true;
    }
}

 

相关题目

659. Split Array into Consecutive Subsequences

846. Hand of Straights

1296. Divide Array in Sets of K Consecutive Numbers

LeetCode 题目总结