Sure! Here's a test case generator for the "Soccer" problem statement. This generator will create random test cases within the constraints specified in the problem.

```python
import random

def tcgen():
    # Generate random H and W within the given constraints
    H = random.randint(1, 500)
    W = random.randint(1, 500)
    
    # Generate A, B, C within the given constraints
    A = random.randint(0, 1_000_000_000)
    B = random.randint(0, 1_000_000_000)
    C = random.randint(0, 1_000_000_000)
    
    # Generate N within the given constraints
    N = random.randint(2, 100_000)
    
    # Generate unique starting positions for N players within the field boundaries
    players = set()
    while len(players) < N:
        Si = random.randint(0, H)
        Ti = random.randint(0, W)
        players.add((Si, Ti))
    players = list(players)
    
    # Ensure the first and last players are at different positions
    if players[0] == players[-1]:
        players[-1] = (random.randint(0, H), random.randint(0, W))
        while players[-1] == players[0]:
            players[-1] = (random.randint(0, H), random.randint(0, W))
    
    # Convert player positions to the required format
    player_positions = "\n".join(f"{Si} {Ti}" for Si, Ti in players)
    
    # Generate the complete input string
    input_data = f"{H} {W}\n{A} {B} {C}\n{N}\n{player_positions}"
    
    return input_data

# Example usage
for _ in range(3):
    print(tcgen())
    print()
```

This function generates:
1. Random values for `H`, `W`, `A`, `B`, and `C` within their respective constraints.
2. A random number of players `N` between 2 and 100,000.
3. Random unique positions `(Si, Ti)` for each player within the field boundaries.
4. Ensures that the first player and the last player are at different positions.
5. Formats the generated test case as a string to match the input format of the problem.

You can run this function to generate different test cases for the problem and print them for verification.