Solutions by Lubos Kolouch.

# The Weekly Challenge - 335

## Task 1: Common Characters

### Description

Given an array of words, return every character that appears in each word,
including duplicates. For example, `("bella", "label", "roller")` should yield
`("e", "l", "l")`.

### Solution

#### Perl (ch-1.pl)

Builds frequency tables for every word and keeps the minimum count for each
character across all words. The retained characters are emitted according to
that minimum count. Unit tests cover the five official examples.

#### Python (ch-1.py)

Uses `collections.Counter` intersection (`&`) to compute the shared character
counts, then expands the characters sorted alphabetically. Includes `unittest`
cases mirroring the provided inputs.

### Examples

- Example 1: `("bella", "label", "roller")` → `("e", "l", "l")`
- Example 2: `("cool", "lock", "cook")` → `("c", "o")`
- Example 3: `("hello", "world", "pole")` → `("l", "o")`
- Example 4: `("abc", "def", "ghi")` → `()`
- Example 5: `("aab", "aac", "aaa")` → `("a", "a")`

## Task 2: Find Winner

### Description

Analyze a tic-tac-toe game described by a sequence of moves. Players alternate
starting with A. Report `A` or `B` if a winner is decided, `Draw` if all nine
moves finish without a winner, or `Pending` otherwise.

### Solution

#### Perl (ch-2.pl)

Applies each move to a 3×3 board, checks rows, columns, and diagonals for a win,
and returns the appropriate outcome. Embeds `Test::More` subtests for all five
examples.

#### Python (ch-2.py)

Replicates the board logic using lists, verifies win conditions, and determines
the resulting state. The accompanying `unittest` suite exercises all official
scenarios.

### Examples

- Example 1: `[[0,0],[2,0],[1,1],[2,1],[2,2]]` → `A`
- Example 2: `[[0,0],[1,1],[0,1],[0,2],[1,0],[2,0]]` → `B`
- Example 3: `[[0,0],[1,1],[2,0],[1,0],[1,2],[2,1],[0,1],[0,2],[2,2]]` → `Draw`
- Example 4: `[[0,0],[1,1]]` → `Pending`
- Example 5: `[[1,1],[0,0],[2,2],[0,1],[1,0],[0,2]]` → `B`

## Running the Code

### Perl

```bash
perl ch-1.pl
perl ch-2.pl
```

### Python

```bash
python3 ch-1.py
python3 ch-2.py
```