经常会遇到字符串全排列的问题.例如:输入为{‘a’,’b’,’c’},则其全排列组合为abc,acb,bac,bca,cba,cab.对于输入长度为n的字符串数组,全排列组合为n!种. package Bayes; public class RecursionTree { public static void permutation(char[] s,int from,int to) { if(to<=1) { return; } if(from ==to) { System.out.print