Denial of Service Attack Prevention

Analyze this contract for denial of service vulnerabilities:

```
${{CONTRACT_CODE}}
```

Contract Functions: ${{MAIN_FUNCTIONS}}

DoS analysis:
1. Gas limit vulnerabilities:
   - Unbounded loops
   - External call failures
   - Storage operations
2. Block stuffing susceptibility
3. Griefing attack vectors
4. Push vs pull payment patterns
5. Array manipulation risks
6. Mapping iteration issues
7. External dependency failures
8. Self-destruct impacts
9. Prevention strategies:
   - Pagination implementation
   - Pull payment patterns
   - Gas stipend handling
10. Code fixes with examples

Include gas estimation for vulnerable functions.