159 Longest Substring with At Most Two Distinct Characters

public int lengthOfLongestSubstringTwoDistinct(String s) {
    int maxSize = 0;
    int j = 0;
    int[] hash = new int[256];
    int distinctCount = 0;
    for(int i = 0; i < s.length(); i++){
        while(j < s.length()){
            if(distinctCount == 2 && hash[s.charAt(j)] == 0)
                break;
            if(hash[s.charAt(j)] == 0) distinctCount ++;
            hash[s.charAt(j++)]++;
        } 
        if(j - i > maxSize){
            maxSize = j - i;
        } 
        hash[s.charAt(i)]--;
        if(hash[s.charAt(i)] == 0) distinctCount --;
    }
    return maxSize;
}