题目描述:输入一个字符串,按字典序打印出该字符串中字符的所有排列。例如输
入字符串 abc, 则打印出由字符 a,b,c 所能排列出来的所有字符串 abc,acb,bac,bca,cab 和 cba 。 思路 :将当前位置的字符和前一个字符位置交换,递归。public class Test { public static void main(String[] args) { char[] chars = {'a', 'b', 'c'}; List<String> resList = new ArrayList<>(); permute(chars,0,resList); System.out.println(resList.stream().sorted().collect(Collectors.toList())); } public static void permute(char[] chars, int index, List<String> resList) { if (index == chars.length - 1) { resList.add(String.valueOf(chars)); return; } for (int i = index; i < chars.length; i++) { if (i == index || chars[index] != chars[i]) { swap(chars, index, i); permute(chars, index + 1, resList); swap(chars, index, i); } } } public static void swap(char[] chars, int i, int j) { char c = chars[i]; chars[i] = chars[j]; chars[j] = c; } }