leetcode

0 class Solution {

1 public:

2 int longestSubstring(const string &s, int k) const {

3 const int n = size(s);

4 static int count[26];

5 int res = 0, maxUnique = 0;

6

7 memset(count, 0x00, sizeof(count));

8 for (const char c : s)

9 maxUnique += !count[c - 'a']++;

10

11 for (int l = 1; l <= maxUnique; l++) {

12 memset(count, 0x00, sizeof(count));

13 int i = 0, j = 0, unique = 0, least = 0;

14 while (j < n) {

15 if (unique <= l) {

16 unique += !count[s[j] - 'a']++;

17 least += count[s[j] - 'a'] == k;

18 j++;

19 } else {

20 least -= count[s[i] - 'a'] == k;

21 unique -= !--count[s[i] - 'a'];

22 i++;

23 }

24

25 if (unique == l && least == l) {

26 res = max(res, j - i);

27 }

28 }

29 }

30

31 return res;

32 }

33 };