Your task is to find the first element of an array that is not consecutive.

By not consecutive we mean not exactly 1 larger than the previous element of the array.

E.g. If we have an array `[1,2,3,4,6,7,8]` then `1` then `2` then `3` then `4` are all consecutive but `6` is not, so that's the first non-consecutive number.

```if:c
If a non consecutive number is found then return `true` and set the passed in pointer to the number found.

If the whole array is consecutive then return `false`.
```
```if-not:c
If the whole array is consecutive then return `null`^(2).
```
The array will always have at least `2` elements^(1) and all elements will be numbers. The numbers will also all be unique and in ascending order. The numbers could be positive or negative and the first non-consecutive could be either too!

If you like this Kata, maybe try this one next: https://www.codewars.com/kata/represent-array-of-numbers-as-ranges

```if:c
^(1) Can you write a solution that will return `false` for both `[]` and `[ x ]` (an empty array and one with a single number) though? (This is an empty array and one with a single number and is not tested for, but you can write your own example test. )
```
```if-not:c
^(1) Can you write a solution that will return `null`^(2) for both `[]` and `[ x ]` though?  (This is an empty array and one with a single number and is not tested for, but you can write your own example test. )

^(2)  
Swift, Ruby and Crystal: `nil`  
Haskell: `Nothing`  
Python, Rust: `None`  
Julia: `nothing`  
Nim: `none(int)` (See [options](https://nim-lang.org/docs/options.html))
```

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = 'def first_non_consecutive(arr):\n    if len(arr) == 2:\n        return None\n    elem_1 = arr[0]\n    elem_2 = arr[1]\n    elem_3 = arr[2]\n    diff_1 = elem_2 - elem_1\n    diff_2 = elem_3 - elem_2\n    if diff_1 > diff_2:\n        grade_1 = diff_2\n    elif diff_1 < diff_2:\n        grade_1 = diff_1\n    else:\n        grade_1 = diff_1\n    for i in range(0, len(arr) - 1):\n        if arr[i + 1] != arr[i] + grade_1:\n            return arr[i + 1]\n    \n    return None'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'first_non_consecutive'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 5560