字符串各种组合 -- 算法

 
  public static void traversal(char[] chss, int index){
      for(int i = index; i < chss.length; i ++) {
          char[] chs = chss.clone(); 
          char temp = chs[index];   //swap item
          chs[index] = chs[i];
          chs[i] = temp;
          if(index == chs.length-1) {
              System.out.println(new String(chs));
              break;
          }
          traversal(chs, index+1);
      }
  }

 

public static void main(String args[]) throws Exception {
   String str = "abcd";
      char[] chs = str.toCharArray();
      traversal(chs, 0);
  }