846. Hand of Straights

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.

Note:

1. 1 <= hand.length <= 10000
2. 0 <= hand[i] <= 10^9
3. 1 <= W <= hand.length

class Solution {

public:

    bool isNStraightHand(vector<int>& hand, int W) {

        int n = hand.size();

        if(n%W!=0){

            return false;

        }

        map<int,int> mp;

        for(int i = 0; i < n ; i++){

            mp[hand[i]]++;

        }

        while(!mp.empty()){

            int v = mp.begin()->first;

            for(int i = 0; i < W; i++){

                if(!mp[v+i]){

                    return false;

                }else{

                    mp[v+i]--;

                    if(!mp[v+i]){

                        mp.erase(v+i);

                    }

                }

            }

        }

        return true;

        

    }

};