Leetcode 1248. Count "graceful subarray" prefix and

Original link ：Leetcode 1248. Statistics 「 Graceful subarray 」

class Solution {
    
public:
    int numberOfSubarrays(vector<int>& nums, int k) {
    
        int n = (int)nums.size();
        vector<int> cnt(n+1,0);
        int res=0,tmp=0;
        cnt[0]=1;
        for(int i=0;i<nums.size();i++)
        {
    
            tmp+=nums[i]&1;
            res+= tmp>=k ? cnt[tmp-k]:0;
            cnt[tmp]++;
        }
        return res;
    }
};