Codeforces Round 685 (Div. 2) |
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Finished |
Ashish has two strings $$$a$$$ and $$$b$$$, each of length $$$n$$$, and an integer $$$k$$$. The strings only contain lowercase English letters.
He wants to convert string $$$a$$$ into string $$$b$$$ by performing some (possibly zero) operations on $$$a$$$.
In one move, he can either
Note that he can perform any number of operations, and the operations can only be performed on string $$$a$$$.
Help Ashish determine if it is possible to convert string $$$a$$$ into $$$b$$$ after performing some (possibly zero) operations on it.
The first line contains a single integer $$$t$$$ ($$$1 \leq t \leq 10^5$$$) — the number of test cases. The description of each test case is as follows.
The first line of each test case contains two integers $$$n$$$ ($$$2 \leq n \leq 10^6$$$) and $$$k$$$ ($$$1 \leq k \leq n$$$).
The second line of each test case contains the string $$$a$$$ of length $$$n$$$ consisting of lowercase English letters.
The third line of each test case contains the string $$$b$$$ of length $$$n$$$ consisting of lowercase English letters.
It is guaranteed that the sum of values $$$n$$$ among all test cases does not exceed $$$10^6$$$.
For each test case, print "Yes" if Ashish can convert $$$a$$$ into $$$b$$$ after some moves, else print "No".
You may print the letters of the answer in any case (upper or lower).
4 3 3 abc bcd 4 2 abba azza 2 1 zz aa 6 2 aaabba ddddcc
No Yes No Yes
In the first test case it can be shown that it is impossible to convert $$$a$$$ into $$$b$$$.
In the second test case,
"abba" $$$\xrightarrow{\text{inc}}$$$ "acca" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "azza".
Here "swap" denotes an operation of the first type, and "inc" denotes an operation of the second type.
In the fourth test case,
"aaabba" $$$\xrightarrow{\text{swap}}$$$ "aaabab" $$$\xrightarrow{\text{swap}}$$$ "aaaabb" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "ddaabb" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "ddddbb" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "ddddcc".
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