LeetCode-89. 格雷编码-Java-medium

题目链接

法一

    /**
     * G(i) = i ^ (i/2)
     * 例如 n = 3
     * G(0) = 000,
     * G(1) = 1 ^ 0 = 001 ^ 000 = 001
     * G(2) = 2 ^ 1 = 010 ^ 001 = 011
     * G(3) = 3 ^ 1 = 011 ^ 001 = 010
     * G(4) = 4 ^ 2 = 100 ^ 010 = 110
     * G(5) = 5 ^ 2 = 101 ^ 010 = 111
     * G(6) = 6 ^ 3 = 110 ^ 011 = 101
     * G(7) = 7 ^ 3 = 111 ^ 011 = 100
     *
     * @param n
     * @return
     */
    public List<Integer> grayCode(int n) {
        List<Integer> code = new LinkedList<>();
        for (int i = 0; i < 1 << n; i++) { // 1 << n，即2^n
            code.add(i ^ i >> 1); // i >> 1，即n/2
        }
        return code;
    }

本地测试

        /**
         * 89. 格雷编码
         */
        lay.showTitle(89);
        Solution89 sol89 = new Solution89();
        List<Integer> code89 = sol89.grayCode(3);
        System.out.println(code89.toString());