213. House Robber II

• dp 解法

    /**
     * 转化为
     * Max(rob(nums[0:n-1]), rob(nums[1:n]))
     */
    public int rob(int[] nums) {
        if (nums.length == 0) {
            return 0;
        }
        if (nums.length == 1) {
            return nums[0];
        }
        int[] pre = Arrays.copyOfRange(nums, 0, nums.length-1);
        int[] after = Arrays.copyOfRange(nums, 1, nums.length);
        return Math.max(subRob(pre), subRob(after));
    }

    private int subRob(int[] nums) {
        int[] dp = new int[nums.length + 2];
        for (int i = 0; i < nums.length; i++) {
            dp[i + 2] = Math.max(dp[i] + nums[i], dp[i + 1]);
        }
        return dp[nums.length + 1];
    }