Codeforces Global Round 10
C
Omkar and Waterslide
Codeforces
1200
原题
← BD →
翻译中…

Omkar is building a waterslide in his water park, and he needs your help to ensure that he does it as efficiently as possible.

翻译中…

Omkar currently has $n$ supports arranged in a line, the $i$-th of which has height $a_i$. Omkar wants to build his waterslide from the right to the left, so his supports must be nondecreasing in height in order to support the waterslide. In $1$ operation, Omkar can do the following: take any contiguous subsegment of supports which is nondecreasing by heights and add $1$ to each of their heights.

翻译中…

Help Omkar find the minimum number of operations he needs to perform to make his supports able to support his waterslide!

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An array $b$ is a subsegment of an array $c$ if $b$ can be obtained from $c$ by deletion of several (possibly zero or all) elements from the beginning and several (possibly zero or all) elements from the end.

翻译中…

An array $b_1, b_2, \dots, b_n$ is called nondecreasing if $b_i\le b_{i+1}$ for every $i$ from $1$ to $n-1$.

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Input

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Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \leq t \leq 100$). Description of the test cases follows.

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The first line of each test case contains an integer $n$ ($1 \leq n \leq 2 \cdot 10^5$) — the number of supports Omkar has.

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The second line of each test case contains $n$ integers $a_{1},a_{2},...,a_{n}$ $(0 \leq a_{i} \leq 10^9)$ — the heights of the supports.

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It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$.

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Output

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For each test case, output a single integer — the minimum number of operations Omkar needs to perform to make his supports able to support his waterslide.

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Note

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The subarray with which Omkar performs the operation is bolded.

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In the first test case:

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  • First operation:$[5, 3, \textbf{2}, 5] \to [5, 3, \textbf{3}, 5]$
  • Second operation:$[5, \textbf{3}, \textbf{3}, 5] \to [5, \textbf{4}, \textbf{4}, 5]$
  • Third operation:$[5, \textbf{4}, \textbf{4}, 5] \to [5, \textbf{5}, \textbf{5}, 5]$
翻译中…

In the third test case, the array is already nondecreasing, so Omkar does $0$ operations.

翻译中…

样例

Input #1
3
4
5 3 2 5
5
1 2 3 5 3
3
1 1 1
Output #1
3
2
0
InputCopy OutputCopy
题目信息
题号
1392C
时间限制
2 s
内存限制
256 MB
标签
贪心
模拟

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。