class Solution {
public:
    /*
	参考打家劫舍I，封装函数，分别去头去尾计算完了求最大值即可
     */
    int maxValue(int a, int b, vector<int>& nums){
        int prev = 0, cur = 0, tmp = 0;
        for(int i = a; i <= b; ++i){
            tmp = cur;
            cur = max(cur, nums[i] + prev);
            prev = tmp;
        }
        return cur;
    }

    int rob(vector<int>& nums) {
        return max(maxValue(1, nums.size()-1, nums), maxValue(0, nums.size() - 2, nums));
    }
};