char[] cs = "abcd".toCharArray();
        int max = (int) Math.pow(2, cs.length);
        StringBuilder buffer = new StringBuilder();
        for (int i = 1; i < max; i++) {
            buffer.setLength(0);
            for (int j = 0;j<cs.length;j++) {
                if (((i>>j) & 1)>0) {
                    buffer.append(cs[j]);
                }
            }
            System.out.println(buffer);
        }

【 在 iStudy 的大作中提到: 】
: a,b,c,d四个对象
: 我要生成a,b,c,d的全组合===C(4,1)+C(4,2)+C(4,3)+C(4,4)
: 结果就是输出 {a,b,c,d, ab,ac,ad,bc,bd,cd,abc,abd,acd,bcd,abcd}
: ...................
--
修改:zms FROM 43.224.44.74
FROM 43.224.44.74