Divide Array in Sets of K Consecutive Numbers

Description

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/

Solution(javascript)

/** Greedy 对比659
 * @param {number[]} nums
 * @param {number} k
 * @return {boolean}
 */
const isPossibleDivide = function (nums, k) {
  const sorted = nums.sort((a, b) => a - b)
  const needed = {}
  let neededCount = 0
  for (const num of sorted) {
    if (!needed[num]) {
      for (let i = num + 1; i <= num + k - 1; i++) {
        needed[i] = (needed[i] || 0) + 1
      }
      neededCount += k - 1
    } else {
      needed[num] -= 1
      neededCount -= 1
    }
  }
  return neededCount === 0
}