Leet Code Daily 2024-06-06 - Hand of Straights

class Solution {
public:
    bool isNStraightHand(vector<int>& hand, int groupSize) {
        unordered_map<int, int> cnt_unused;
        for (const auto& val : hand) {
            cnt_unused[val]++;
        }
        sort(hand.begin(), hand.end());
        for (const auto& val : hand) {
            if (cnt_unused[val] > 0) {
                for (int i = val; i < val + groupSize; i++) {
                    if (cnt_unused[i] < 1) {
                        return false;
                    }
                    cnt_unused[i]--;
                }
            }
        }
        return true;
    }
};