LeetCode:Longest Substring Without Repeating Characters

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for “abcabcbb” is “abc”, which the length is 3. For “bbbbb” the longest substring is “b”, with the length of 1.

    public static int lengthOfLongestSubstring(String s) {
        if(s == null || s.trim().length() == 0){
            return 0;
        }
        s = s.trim();
        int len = s.length();
        //char类型8位最多可表示256种字符
        int[] arrayOfIndex = new int[256];
        Arrays.fill(arrayOfIndex,-1);
        int bIndex = 0, tmpLen = 0, maxLen = 0;
        char c;
        for(int i=0; i<len; i++){
            c = s.charAt(i);
            //发现重复字符，保证重复字符在当前子字符串内
            if(arrayOfIndex[c] >= bIndex){
                maxLen = maxLen > tmpLen ? maxLen : tmpLen;
                //重置子字符串的起始位置，该位置有可能在上一个子字符串的内部
                bIndex = arrayOfIndex[c]+1;
                //重置子字符串的长度
                tmpLen = i-arrayOfIndex[c]-1;
            }
            tmpLen++;
            //记录当前字符在字符串中的位置
            arrayOfIndex[c] = i;
        }
        return maxLen > tmpLen ? maxLen : tmpLen;
    }