2018/11/2

打印一个字符串的全部子序列，包括空字符串

public class SubSequences {
    /**
     * 打印字符串的所有子序列
     *
     * @param chars   字符数组
     * @param index 当前所在的字符位置
     * @param res   之前获得的子序列
     */
    public static void printSubSequences(char[] chars, int index, String res) {
        if (index == chars.length) {
            System.out.print(res + " ");
            return;
        }
        printSubSequences(chars,index+1,res);
        printSubSequences(chars,index+1,res+chars[index]);
    }

    public static void main(String[] args) {
        String test = "abc";
        printSubSequences(test.toCharArray(),0,"");
    }
}