Note: This is an extension of House Robber.
After robbing those houses on that street, the thief has found himself a new place for his thievery so that he will not get too much attention. This time, all houses at this place are arranged in a circle. That means the first house is the neighbor of the last one. Meanwhile, the security system for these houses remain the same as for those in the previous street.
Given a list of non-negative integers representing the amount of money of each house, determine the maximum amount of money you can rob tonight without alerting the police.
解题思路：
可以分解为两种情况：包含nums[0]和不包含nums[0]，分别求解算出最大即可，JAVA实现如下；
public int rob(int[] nums) {
if (nums == null || nums.length == 0)
return 0;
else if (nums.length <= 2)
return Math.max(nums[0], nums[nums.length - 1]);
else if(nums.length==3)
return Math.max(nums[0], Math.max(nums[1],nums[2]));
int res = 0;
int[] dp = new int[nums.length];
dp[0] = nums[0];
dp[2] = nums[0] + nums[2];
dp[3] = nums[0] + nums[3];
for (int i = 4; i < nums.length-1; i++)
dp[i] = nums[i] + Math.max(dp[i - 2], dp[i - 3]);
res=Math.max(dp[nums.length-2],dp[nums.length-3]);
dp[1] = nums[1];
dp[2] = nums[2];
dp[3] = nums[3] + nums[1];
for (int i = 4; i < nums.length; i++)
dp[i] = nums[i] + Math.max(dp[i - 2], dp[i - 3]);
return Math.max(res, Math.max(dp[nums.length-1],dp[nums.length-2]));
}