Every 3 days one leetcode, the second question: LongestSubstringWithoutRepeatingCharacters

1. Find the longest substring without repetition

//82 ms 38.2 MB public int lengthOfLongestSubstring(String s) {maxNum = 0;for (int i = 0, size = s.length(); i < size; i++) {
            for (int j = i + 1; j <= size; j++) {
                String temp = s.substring(i, j);
                if (j == size) {
                    maxNum = Math.max(size - i,maxNum);
                } else if (temp.indexOf(s.charAt(j)) != -1) {
                    if (temp.length() > maxNum) {
                        maxNum = temp.length();
                    }
                    break; }}}returnmaxNum; } / / 10 ms 37.2 MB public int lengthOfLongestSubstring2 (String s) {int maxNum = 0; LinkedList<Character> linkedList = new LinkedList<>(); int i = 0, j = 0, size = s.length();while (i < size && j < size) {
            char at = s.charAt(j);
            if (linkedList.contains(at)) {
                linkedList.remove((Object) s.charAt(i));
                i++;
            } else{ linkedList.add(at); j++; maxNum = Math.max(j - i, maxNum); }}return maxNum;
    }
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