不含重复字符的最长子串:
public int longestSubStr(String str) { int max = 0; Deque<Character> deque = new ArrayDeque<>(); for (int i = 0; i < str.length(); i++) { if (!deque.contains(str.charAt(i))) { deque.addLast(str.charAt(i)); } else { max = Math.max(max, deque.size()); while (deque.peek() != str.charAt(i)) { deque.removeFirst(); } deque.removeFirst(); deque.addLast(str.charAt(i)); } } max = Math.max(max, deque.size()); return max; }