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Problem B
Long Swaps
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Nick Youngson
You have a string $s$ and you may modify it by making long swaps of its letters. Two letters can be swapped if their positions differ by at least $k$. That is, you may swap the $i$-th letter with the $j$-th letter in $s$ if $|i - j| \geq k$. Is it possible to sort all the letters in $s$ increasingly, if you are allowed to swap any number of times (possibly zero)?
Input
The first line has a string $s$ ($2 \leq |s| \leq 100$) and an integer $k$ ($1 \leq k \leq |s| - 1$), separated by a single space. The string $s$ consists of only lowercase letters.
Output
If it is possible to sort the letters increasingly, output “Yes”. Otherwise output “No”.
| Sample Input 1 | Sample Output 1 |
|---|---|
prognova 4 |
Yes |
| Sample Input 2 | Sample Output 2 |
|---|---|
helloworld 6 |
No |
