Grokking the Coding Interview: Patterns for Coding Questions

Solution: Problem Challenge 1: Evaluate Expression

## Problem Statement

Given an expression containing digits and operations (+, -, *), find all possible ways in which the expression can be evaluated by grouping the numbers and operators using parentheses.

**Example 1**:
```
Input: "1+2*3"
Output: 7, 9
Explanation: 
  1+(2*3) => 7
  (1+2)*3 => 9
```
**Example 2**:
```
Input: "2*3-4-5"
Output: 8, -12, 7, -7, -3 
Explanation: 
  2*(3-(4-5)) => 8
  2*(3-4-5) => -12
  2*3-(4-5) => 7
  2*(3-4)-5 => -7
  (2*3)-4-5 => -3
```

## Solution

This problem follows the `Subsets` pattern and can be mapped to `Balanced Parentheses`