Digital root
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Description
Today at the lesson of mathematics, Petya learns about the digital root.
The digital root of a non-negative integer is the single digit value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit sum. The process continues until a single-digit number is reached.
Let's denote the digital root of $x$ as $S(x)$. Then $S(5)=5$, $S(38)=S(3+8=11)=S(1+1=2)=2$, $S(10)=S(1+0=1)=1$.
As a homework Petya got $n$ tasks of the form: find $k$-th positive number whose digital root is $x$.
Petya has already solved all the problems, but he doesn't know if it's right. Your task is to solve all $n$ tasks from Petya's homework.
The first line contains a single integer $n$ ($1 \le n \le 10^3$) — the number of tasks in Petya's homework. The next $n$ lines contain two integers $k_i$ ($1 \le k_i \le 10^{12}$) and $x_i$ ($1 \le x_i \le 9$) — $i$-th Petya's task in which you need to find a $k_i$-th positive number, the digital root of which is $x_i$.
Output $n$ lines, $i$-th line should contain a single integer — the answer to the $i$-th problem.
Input
The first line contains a single integer $n$ ($1 \le n \le 10^3$) — the number of tasks in Petya's homework. The next $n$ lines contain two integers $k_i$ ($1 \le k_i \le 10^{12}$) and $x_i$ ($1 \le x_i \le 9$) — $i$-th Petya's task in which you need to find a $k_i$-th positive number, the digital root of which is $x_i$.
Output
Output $n$ lines, $i$-th line should contain a single integer — the answer to the $i$-th problem.
3
1 5
5 2
3 1
5
38
19
20240618集训
- Status
- Done
- Rule
- IOI
- Problem
- 7
- Start at
- 2024-6-18 19:00
- End at
- 2024-6-18 21:00
- Duration
- 2 hour(s)
- Host
-
SamuelXuch
- Partic.
- 12