Codeforces Round 885 (Div. 2)
D
Vika and Bonuses
Codeforces
2200
原题
← CE →
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A new bonus system has been introduced at Vika's favorite cosmetics store, "Golden Pear"!

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The system works as follows: suppose a customer has $b$ bonuses. Before paying for the purchase, the customer can choose one of two options:

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  • Get a discount equal to the current number of bonuses, while the bonuses are not deducted.
  • Accumulate an additional $x$ bonuses, where $x$ is the last digit of the number $b$. As a result, the customer's account will have $b+x$ bonuses.
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For example, if a customer had $24$ bonuses, he can either get a discount of $24$ or accumulate an additional $4$ bonuses, after which his account will have $28$ bonuses.

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At the moment, Vika has already accumulated $s$ bonuses.

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The girl knows that during the remaining time of the bonus system, she will make $k$ more purchases at the "Golden Pear" store network.

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After familiarizing herself with the rules of the bonus system, Vika became interested in the maximum total discount she can get.

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Help the girl answer this question.

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Input

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Each test consists of multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 10^5$) — the number of test cases. The description of the test cases follows.

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The test case consists of a single line containing two integers $s$ and $k$ ($0 \le s \le 10^9$, $1 \le k \le 10^9$) — the current number of bonuses in Vika's account and how many more purchases the girl will make.

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Output

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For each test case, output a single integer — the maximum total discount that can be obtained through the bonus system.

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Note

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In the first test case, Vika can accumulate bonuses after the first and second purchases, after which she can get a discount of $4$.

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In the second test case, Vika can get a discount of $11$ three times, and the total discount will be $33$.

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In the third example, regardless of Vika's actions, she will always get a total discount of $0$.

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样例

Input #1
6
1 3
11 3
0 179
5 1000000000
723252212 856168102
728598293 145725253
Output #1
4
33
0
9999999990
1252047198518668448
106175170582793129
InputCopy OutputCopy
题目信息
题号
1848D
时间限制
3 s
内存限制
256 MB
标签
二分
暴力
数学
三分

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