13 人解决，41 人已尝试。
22 份提交通过，共有 231 份提交。
7.4 EMB 奖励。
单点时限: 10.0 sec
内存限制: 256 MB
We are given a sequence a1, …, an. We can manipulate this sequence using the operation reduce(i), which replaces elements ai and ai+1 with a single element max(ai, ai+1), resulting in a new shorter sequence. The cost of this operation is max(ai, ai+1). After n - 1 operations reduce, we obtain a sequence of length 1. Our task is to compute the cost of the optimal reducing scheme, i.e. the sequence of reduce operations with minimal cost leading to a sequence of length 1.
The first line contains n (1 ≤n ≤1,000,000), the length of the sequence. The following n lines contain one integer ai, the elements of the sequence (0 ≤ai ≤1,000,000,000).
In the first and only line of the output print the minimal cost of reducing the sequence to a single element.
3 1 2 3
5
13 人解决，41 人已尝试。
22 份提交通过，共有 231 份提交。
7.4 EMB 奖励。