Reason · Medium
The missing number
A list of numbers goes up in equal steps, but one number is missing. The numbers may be in any order.
Task
Write a prompt that finds the missing number.
Output format
<number>
- If nothing is missing, return NONE.
Your prompt must contain {input}: it is replaced by each test case, just like the hidden tests in a hiring test.
Sample case 1
Input
2, 4, 8, 10
Output
6
Sample case 2
Input
15 5 20 25
Output
10
There are 4 test cases in all; the others are like hidden tests: work out what tricky inputs they might use!