GLM 5.2 vs Grok 4.5 for coding

Here is a regex for validating UK postcodes:

`^[A-Z]{1,2}\d[A-Z\d]?\s?\d[A-Z]{2}$`

**Explanation of each part:**
* `^` : Asserts the position at the start of the string.
* `[A-Z]{1,2}` : Matches one or two uppercase letters for the first part of the outward code.
* `\d` : Matches exactly one digit for the outward code.
* `[A-Z\d]?` : Optionally matches one uppercase letter or digit to complete the outward code.
* `\s?` : Optionally matches a single space separating the outward and inward codes.
* `\d` : Matches exactly one digit for the start…

**Regex:** `/^[A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}$/i`

- `^` — start of string  
- `[A-Z]{1,2}` — 1–2 letters (area)  
- `\d` — one digit (district start)  
- `[A-Z\d]?` — optional letter or digit (rest of district)  
- ` ?` — optional space  
- `\d` — one digit (sector)  
- `[A-Z]{2}` — two letters (unit)  
- `$` — end of string  
- `i` flag — case-insensitive  

Two valid UK postcodes this would reject: `EC1A 1BB` (the `A` after the digit in the outward code is only partially covered by the optional class in some edge positions), `W1A 0AX` (same…