Codeforces Round 986 (Div. 2)
C
Alice's Adventures in Cutting Cake
Codeforces
1600
原题
← BD →
翻译中…

Alice is at the Mad Hatter's tea party! There is a long sheet cake made up of $n$ sections with tastiness values $a_1, a_2, \ldots, a_n$. There are $m$ creatures at the tea party, excluding Alice.

翻译中…

Alice will cut the cake into $m + 1$ pieces. Formally, she will partition the cake into $m + 1$ subarrays, where each subarray consists of some number of adjacent sections. The tastiness of a piece is the sum of tastiness of its sections. Afterwards, she will divvy these $m + 1$ pieces up among the $m$ creatures and herself (her piece can be empty). However, each of the $m$ creatures will only be happy when the tastiness of its piece is $v$ or more.

翻译中…

Alice wants to make sure every creature is happy. Limited by this condition, she also wants to maximize the tastiness of her own piece. Can you help Alice find the maximum tastiness her piece can have? If there is no way to make sure every creature is happy, output $-1$.

翻译中…

Input

翻译中…

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). The description of the test cases follows.

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The first line of each test case contains three integers $n, m, v$ ($1\le m\le n\le 2\cdot 10^5$; $1\le v\le 10^9$) — the number of sections, the number of creatures, and the creatures' minimum requirement for tastiness, respectively.

翻译中…

The next line contains $n$ space separated integers $a_1, a_2, \ldots, a_n$ ($1 \le a_i \le 10^9$) — the tastinesses of the sections.

翻译中…

The sum of $n$ over all test cases does not exceed $2\cdot 10^5$.

翻译中…

Output

翻译中…

For each test case, output the maximum tastiness Alice can achieve for her piece, or $-1$ if there is no way to make sure every creature is happy.

翻译中…

Note

翻译中…

For the first test case, Alice can give the first and second section as their own pieces, and then take the remaining $10 + 1 + 1 + 10 = 22$ tastiness for herself. We can show that she cannot do any better.

翻译中…

For the second test case, Alice could give the first and second section as one piece, and the sixth section as one piece. She can then take the remaining $10 + 1 + 1 = 12$ tastiness for herself. We can show that she cannot do any better.

翻译中…

For the seventh test case, Alice cannot give each creature a piece of at least $12$ tastiness.

翻译中…

样例

Input #1
7
6 2 1
1 1 10 1 1 10
6 2 2
1 1 10 1 1 10
6 2 3
1 1 10 1 1 10
6 2 10
1 1 10 1 1 10
6 2 11
1 1 10 1 1 10
6 2 12
1 1 10 1 1 10
6 2 12
1 1 1 1 10 10
Output #1
22
12
2
2
2
0
-1
InputCopy OutputCopy
题目信息
题号
2028C
时间限制
2 s
内存限制
256 MB
标签
二分
动态规划
贪心
双指针

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。