public void get(){ Scanner scanner = new Scanner(System.in); String string = scanner.next(); int length = string.length(); int ans = 0,temp_length = 0; boolean flag = true; // 长度为2时,输出0 if (length == 2 ){ System.out.println(ans); return; } for (int i = 2; i <= length ; i += 2) { flag = true; string = string.substring(0, length - i); temp_length = length - i; for (int j = 0; j < temp_length / 2; j++) { if (string.charAt(j) != string.charAt(temp_length / 2 + j)){ flag = false; break; } } if (flag){ System.out.println(temp_length); return; } } System.out.println(ans); return; } public void show(){ HashMap<Character,Integer> map = new HashMap<>(); Scanner scanner = new Scanner(System.in); String str = scanner.next(); int ans = 0; for (int i = 0; i < str.length(); i++) { Character ch = (Character) str.charAt(i); if (map.containsKey(ch)){ map.put(ch,map.get(ch) + 1); } else { map.put(ch,1); } } Collection<Integer> values = map.values(); Iterator<Integer> iterator = values.iterator(); while (iterator.hasNext()){ Integer tmp = iterator.next(); if (tmp % 2 == 1){ ans ++; } } System.out.println(ans); }