Leetcode 340) Longest Substring with At Most K Distinct Characters

02 Nov 2021 in Algorithms

My Answer

class Solution {
    public int lengthOfLongestSubstringKDistinct(String s, int k) {
        int left =0; int right =0;
        //Characters with values from 128 to 255 are the "Extended" character set.
        int[] charInfo = new int[256];
        int totChar =0; int max=0;
        
        while(right < s.length()){
            charInfo[s.charAt(right)]++;
            if(charInfo[s.charAt(right)]==1){
                totChar++;
            }
            
            while(totChar > k){
                charInfo[s.charAt(left)]--;
                if(charInfo[s.charAt(left)]==0){
                    totChar--;
                }
                left++;
            }
            
            if(max<right-left+1){
                max= right-left+1;
            }
            right++;
    }
        return max;
    }
}