Given a string, find the length of the longest substring T that contains at most k distinct characters.
For example, Given s = “eceba” and k = 2,
T is "ece" which its length is 3.
Solution：滑動窗
思路：
Time Complexity: O(N) Space Complexity: O(1)
Solution Code：
class Solution {
public class Solution {
public int lengthOfLongestSubstringKDistinct(String s, int k) {
int[] count = new int[256];
int num = 0, i = 0, res = 0;
for (int j = 0; j < s.length(); j++) {
if (count[s.charAt(j)]++ == 0) num++;
if (num > k) {
while (--count[s.charAt(i++)] > 0);
num--;
}
res = Math.max(res, j - i + 1);
}
return res;
}
}
}
