字符全排列递归算法

public class Main {

    private static char [] str = {'1','2','3','4'} ;

    public static void main(String[] args) {
        arrange(str.length);
    }

    private static void arrange(int size){
        if (size == 1)
        {
            show();
            return ;
        }
        for (int i= 0 ; i < size ; i ++)
        {
            arrange(size -1);
            shift(size);
        }
    }

    private static void show() {
        for (char c:str)
            System.out.print(c);
        System.out.println();
    }

    /**
     * 将str数组的后size位前移一个位置
     */
    private static void shift(int size) {
        char c = str[str.length - size];
        for (int i=str.length - size + 1 ; i< str.length  ; i ++)
        {
            str[i-1] = str[i];
        }
        str[str.length - 1] = c ;
    }

}