# Past Challenges

## leetle

### 8. Two Sum

**Difficulty:** 71%  
**Time:** 00:00

Write a function `solve` that finds two numbers in a list that add up to a target value. Return a list with their indices in order. If the target cannot be made, return an empty list.

**Example:** `Input: [2, 7, 11, 15], target=9`  
**Output:** `[0, 1]`

Make sure you `return` your solution, don't print!

```python

def solve(nums, target):
    pass
```

### Test Cases

- Test case 1: [2, 7, 11, 15], target=9  
- Test case 2: [3, 2, 4], target=6  
- Test case 3: [3, 3], target=6  
- Test case 4: [1, 2, 3], target=6  
- Test case 5: [], target=0

### Attempts
- Attempt 1: Success  
- Attempt 2: Failure