309267: CF1654A. Maximum Cake Tastiness
Memory Limit:256 MB
Time Limit:2 S
Judge Style:Text Compare
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Description
Maximum Cake Tastiness
题意翻译
给定一个长度为 $n$ 的数组 $a$,定义其权值为 $\max\limits_{1\leqslant i<n}{(a_i+a_{i+1})}$。 你可以选择数组中的任意一个子段并将其翻转,换句话说,你可以选择两个下标 $l,r(1\leqslant l\leqslant r\leqslant n)$,然后将数组变为 $a_1,a_2,\cdots,a_{l-1},\underline{a_r,a_{r-1},\cdots,a_l},a_{r+1},a_{r+2},\cdots,a_n$。 求在执行上述操作至多一次的情况下,数组 $a$ 的权值的最大值。 数据范围: - $t$ 组数据,$1\leqslant t\leqslant 50$。 - $2\leqslant n\leqslant 1000$。 - $1\leqslant a_i\leqslant 10^9$。 Translated by Eason_AC题目描述
There are $ n $ pieces of cake on a line. The $ i $ -th piece of cake has weight $ a_i $ ( $ 1 \leq i \leq n $ ). The tastiness of the cake is the maximum total weight of two adjacent pieces of cake (i. e., $ \max(a_1+a_2,\, a_2+a_3,\, \ldots,\, a_{n-1} + a_{n}) $ ). You want to maximize the tastiness of the cake. You are allowed to do the following operation at most once (doing more operations would ruin the cake): - Choose a contiguous subsegment $ a[l, r] $ of pieces of cake ( $ 1 \leq l \leq r \leq n $ ), and reverse it. The subsegment $ a[l, r] $ of the array $ a $ is the sequence $ a_l, a_{l+1}, \dots, a_r $ . If you reverse it, the array will become $ a_1, a_2, \dots, a_{l-2}, a_{l-1}, \underline{a_r}, \underline{a_{r-1}}, \underline{\dots}, \underline{a_{l+1}}, \underline{a_l}, a_{r+1}, a_{r+2}, \dots, a_{n-1}, a_n $ . For example, if the weights are initially $ [5, 2, 1, 4, 7, 3] $ , you can reverse the subsegment $ a[2, 5] $ , getting $ [5, \underline{7}, \underline{4}, \underline{1}, \underline{2}, 3] $ . The tastiness of the cake is now $ 5 + 7 = 12 $ (while before the operation the tastiness was $ 4+7=11 $ ). Find the maximum tastiness of the cake after doing the operation at most once.输入输出格式
输入格式
The first line contains a single integer $ t $ ( $ 1 \le t \le 50 $ ) — the number of test cases. The first line of each test case contains a single integer $ n $ ( $ 2 \le n \le 1000 $ ) — the number of pieces of cake. The second line of each test case contains $ n $ integers $ a_1, a_2, \ldots, a_n $ ( $ 1 \leq a_i \leq 10^9 $ ) — $ a_i $ is the weight of the $ i $ -th piece of cake.
输出格式
For each test case, print a single integer: the maximum tastiness of the cake after doing the operation at most once.
输入输出样例
输入样例 #1
5
6
5 2 1 4 7 3
3
32 78 78
3
69 54 91
8
999021 999021 999021 999021 999652 999021 999021 999021
2
1000000000 1000000000
输出样例 #1
12
156
160
1998673
2000000000