LeetCode-in-Java
424. Longest Repeating Character Replacement
Medium
You are given a string s and an integer k. You can choose any character of the string and change it to any other uppercase English character. You can perform this operation at most k times.
Return the length of the longest substring containing the same letter you can get after performing the above operations.
Example 1:
Input: s = “ABAB”, k = 2
Output: 4
Explanation: Replace the two ‘A’s with two ‘B’s or vice versa.
Example 2:
Input: s = “AABABBA”, k = 1
Output: 4
Explanation: Replace the one ‘A’ in the middle with ‘B’ and form “AABBBBA”. The substring “BBBB” has the longest repeating letters, which is 4.
Constraints:
1 <= s.length <= 105sconsists of only uppercase English letters.- `0 <= k <= s.length
Solution
public class Solution {
public int characterReplacement(String s, int k) {
int left = 0;
int right = 0;
int len = s.length();
int[] count = new int[256];
char[] sArr = s.toCharArray();
int currMax = 0;
int maxLen = 0;
char curr;
while (right < len) {
curr = sArr[right];
count[curr]++;
currMax = Math.max(currMax, count[curr]);
if (right - left + 1 <= currMax + k) {
maxLen = Math.max(maxLen, right - left + 1);
}
while (right - left + 1 > currMax + k) {
curr = sArr[left];
count[curr]--;
left++;
}
right++;
}
return maxLen;
}
}