CCCGuide

Problem J4: Troublesome Keys

2024 · J4 · Original problem · DMOJ

Problem Description

As Alex is typing, their keyboard is acting strangely. Two letter keys are causing trouble:

Alex presses the silly key at least once but they don’t necessarily press the quiet key.

Your job is to determine the troublesome keys and the wrong letter that is displayed. Luckily, this is possible because Alex never presses the silly key immediately after pressing the quiet key and Alex never presses the quiet key immediately after pressing the silly key.

Input Specification

There will be two lines of input. The first line of input represents the NN keys Alex presses on the keyboard. The second line of input represents the letters displayed on the screen.

Both lines of input will only contain lowercase letters of the alphabet.

The following table shows how the available 1515 marks are distributed.

MarksDescriptionBound
33The quiet key is not pressed. A small number of keys are pressed.N≤50N \leq 50
33The first troublesome key pressed is the silly key. A small number of keys are pressed.N≤50N \leq 50
55The first troublesome key pressed may be the silly key or the quiet key. A small number of keys are pressed.N≤50N \leq 50
4The first troublesome key pressed may be the silly key or the quiet key. A large number of keys are pressed.N≤500 000N \leq 500\,000

Output Specification

There will be two lines of output.

On the first line, output the letter corresponding to the silly key and the wrong letter displayed on the screen when it is pressed, separated by a single space.

On the second line, output the letter corresponding to the quiet key if it is pressed. Output the dash character (-) if the quiet key is not pressed.

Sample Input 1

forloops 
fxrlxxps

Output for Sample Input 1

o x
-

Explanation of Sample Output 1

The letter corresponding to the silly key was the letter o. Each time it was pressed, the wrong letter x was displayed. The quiet key was not pressed.

Sample Input 2

forloops 
fxrlxxp

Output for Sample Input 2

o x
s

Explanation of Sample Output 2

The letter corresponding to the silly key was the letter o. Each time it was pressed, the wrong letter x was displayed. The quiet key corresponds to the letter s which was not displayed.

Sample Input 3

forloops 
frlpz

Output for Sample Input 3

s z
o

Explanation of Sample Output 3

The letter corresponding to the silly key was the letter s. Each time it was pressed, the wrong letter z was displayed. The quiet key corresponds to the letter o which was not displayed.