almostincreasing.py

def first_bad_pair(sequence):
    """Return the first index of a pair of elements where the earlier
    element is not less than the later elements. If no such pair
    exists, return -1."""
    for i in range(len(sequence)-1):
        if sequence[i] >= sequence[i+1]:
            return i
    return -1

def almostIncreasingSequence(sequence):
    """Return whether it is possible to obtain a strictly increasing
    sequence by removing no more than one element from the array."""
    j = first_bad_pair(sequence)
    if j == -1:
        return True  # List is increasing
    if first_bad_pair(sequence[j-1:j] + sequence[j+1:]) == -1:
        return True  # Deleting earlier element makes increasing
    if first_bad_pair(sequence[j:j+1] + sequence[j+2:]) == -1:
        return True  # Deleting later element makes increasing
    return False  # Deleting either does not make increasing