CheckIO - Electronic Station Challenge 4 : Find Sequence

checkio.3.04.findSequence.py

# CheckIO - Electronic Station Challenge 4 : Find Sequence
# http://checkio.org

# You are given a matrix of NxN (4≤N≤10). 
# You should check if there is a sequence of 4 or more matching digits. 
# The sequence may be positioned horizontally, vertically or diagonally (NW-SE or NE-SW diagonals).
# Input: A list of lists. Each list contains integers.
# Output: A boolean. Whether or not a sequence exists.
# Precondition: 0≤N≤10 ∀ x ∈ matrix : 0 < x < 10

def isSequenceInside(array):
    i=0
    sequence=""
    while i<len(array):
        if sequence=="" or str(array[i])==sequence[-1]: 
            sequence+=str(array[i])
            if len(sequence)>3:
                return True
        else:
            sequence=str(array[i])
            if len(array)-i<4:
                return False
        i+=1
    
    
def checkio(matrix):

    # Checking horizontally
    for row in matrix:
        if isSequenceInside(row): return True
        
    # Checking vertically
    for index in range(0,len(matrix)):
        column=[row[index] for row in matrix]
        if isSequenceInside(column): return True
        
    # Checking diagonals
    for i in range(len(matrix)-3):
        diagonal1=[matrix[j+i][j] for j in range(len(matrix)-i)]
        if isSequenceInside(diagonal1): return True
        diagonal2=[matrix[j][j+i] for j in range(len(matrix)-i)]
        if diagonal1!=diagonal2 and isSequenceInside(diagonal2): return True
        diagonal3=[matrix[len(matrix)-1-j-i][j] for j in range(len(matrix)-i)]
        if isSequenceInside(diagonal3): return True
        diagonal4=[matrix[len(matrix)-1-j][j+i] for j in range(len(matrix)-i)]
        if diagonal3!=diagonal4 and isSequenceInside(diagonal4): return True
        
    return False

#These "asserts" using only for self-checking and not necessary for auto-testing
if __name__ == '__main__':
    assert checkio([
        [7, 1, 1, 8, 1, 1],
        [1, 1, 7, 3, 1, 5],
        [2, 3, 1, 2, 5, 1],
        [1, 1, 1, 5, 1, 4],
        [4, 6, 5, 1, 3, 1],
        [1, 1, 9, 1, 2, 1]
    ]) == True, "Diagonal"