Hand of Straights

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.

 

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

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

Solution(javascript)

/**
 * @param {number[]} hand
 * @param {number} W
 * @return {boolean}
 */
var isNStraightHand = function(hand, W) {
    const map = hand.reduce((acc, num) => {
        acc[num] = (acc[num] || 0) + 1
        return acc
    }, {})
    hand.sort((a, b) => a - b)
    for(let num of hand) {
        if(map[num] > 0) {
            for(let i = 0; i < W; i++) {
                if(map[num+i] > 0) {
                    map[num+i] -= 1
                } else {
                    return false
                }
            }
        }
    }
    return true
};