Last updated on October 5th, 2024 at 08:56 pm

Here, We see Longest Repeating Character Replacement LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

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Longest Repeating Character Replacement LeetCode Solution

Problem Statement

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. There may exists other ways to achieve this answer too.

1. Longest Repeating Character Replacement LeetCode Solution C++

class Solution {
public:
    int characterReplacement(string s, int k) {
        int n = s.size();
        int i = 0, j = 0, maxi = 0;
        unordered_map<char,int>mp;
        int ans = -1;
        while(j < n)
        {
            mp[s[j]]++;
            maxi = max(maxi, mp[s[j]]);
            if((j-i+1) - maxi > k){
                mp[s[i]]--;
                i++;
            }
            ans = max(ans, (j-i+1));
            j++;   
        }
        return ans;
    }
};

2. Longest Repeating Character Replacement Solution Java

class Solution {
    public int characterReplacement(String s, int k) 
    {
        int[] count=new int[26];
        int i=0,j=0,max=Integer.MIN_VALUE;
        int result=Integer.MIN_VALUE;
        while(i<s.length())
        {
            count[s.charAt(i)-'A']++;
            max=Math.max(max,count[s.charAt(i)-'A']);
            if(i-j-max+1>k)
            {
                count[s.charAt(j)-'A']--;
                j++;
            }
            result=Math.max(result,i-j+1);
            i++;
        }
        return result;
    }
}

3. Longest Repeating Character Replacement Solution JavaScript

var characterReplacement = function(s, k) {
    var map = [26]
    let largestCount = 0, beg = 0, maxlen = 0;
    for(let end = 0; end < s.length; end++){
        const c = s[end]
        map[c] = (map[c] || 0) + 1
        largestCount = Math.max(largestCount, map[c])
        if(end - beg + 1 - largestCount > k){
            map[s[beg]] -= 1
            beg += 1
        }
        maxlen = Math.max(maxlen, end - beg + 1);
    }
    return maxlen;
};

4. Longest Repeating Character Replacement Solution Python

class Solution(object):
    def characterReplacement(self, s, k):
        maxlen, largestCount = 0, 0
        arr = collections.Counter()
        for idx in xrange(len(s)):
            arr[s[idx]] += 1
            largestCount = max(largestCount, arr[s[idx]])
            if maxlen - largestCount >= k:
                arr[s[idx - maxlen]] -= 1
            else:
                maxlen += 1
        return maxlen