题解 | 打家劫舍(二)

class Solution {
  public:
    int rob(vector<int>& nums) {
        int n = nums.size();
        if (n == 1) return nums[0];

        auto line = [&](int l, int r) -> int {
            int pre2 = 0, pre1 = 0;          // pre2=dp[i-2], pre1=dp[i-1]
            for (int i = l; i <= r; ++i) {
                int cur = max(pre1, pre2 + nums[i]);
                pre2 = pre1;
                pre1 = cur;
            }
            return pre1;
        };

        return max(line(0, n - 2), line(1, n - 1));
    }
};