leetcode

0 class Solution {

1 int atMost(const vector<int> &nums, int k) {

2 static int seen[20001] = {0};

3 memset(seen, 0x00, sizeof(seen));

4

5 int res = 0, j = 0;

6 for (int i = 0; i < nums.size(); i++) {

7 if (!seen[nums[i]]++) k--;

8 while (k < 0)

9 if (!--seen[nums[j++]]) k++;

10 res += i - j + 1;

11 }

12 return res;

13 }

14

15 public:

16 int subarraysWithKDistinct(const vector<int> &nums, int k) {

17 return atMost(nums, k) - atMost(nums, k - 1);

18 }

19 };