Consecutive Runs | Python Fiddle

nums = [1, 2, 3, 5, 10, 9, 8, 9, 10, 11, 7, 8, 7, -1, 0, 1, 182, 181, 180, 179, -1, -2, -3, 5, 6, 6, -8, -7, -6, 2, 4, 6, 12, 15, 18, 15, 12]

def find_consecutive_runs(numbers):
    if not isinstance(numbers, list):
        raise TypeError(f'`numbers` must be a list, received {type(numbers)}')
    
    if not all(isinstance(idx, int) for idx in numbers):
        raise ValueError(f'`numbers` must be a list of integers')
        
    matchedIndices = []
    # runSize is how many consecutive numbers we want to find
    runSize = 3
    # increment is the expected distance between numbers, e.g., multiples of 2, 3, etc
    increment = 1
    
    for idx, num in enumerate(numbers):
        # find last viable start index based on list length
        lastStartIndex = len(numbers) - (runSize - 1)
        # we'll iterate over the list, starting with each subsequent index until we're out of sets
        if idx < lastStartIndex:
            endIdx = idx + runSize
            set = numbers[idx:endIdx]
            base = set[0]
            mapped = []
            
            for x, val in enumerate(set):
                # get the absolute difference between the first number and each number in the list
                absDiff = abs(val - base)
                # since we have an absolute number for the difference, 
                # we can just treat this as positively incrementing
                # as negative numbers will already be handled;
                # so the expected value at any given index is simply the product of the index
                # multipled by the increment value, 
                # allowing for generic handling of any increment size
                # (e.g., idx: 0, inc: 1, idx:1, inc: 1 = 1, idx: 2, inc: 1 = 2)
                expectedIdxValue = x * increment
                mapped.append(absDiff == expectedIdxValue)
        
        if all(mapped):
            matchedIndices.append(idx)
    
    return matchedIndices if len(matchedIndices) else 'None'
            
result = find_consecutive_runs(nums)
print(result)

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