Python/project_euler/problem_18/solution.py

"""
By starting at the top of the triangle below and moving to adjacent numbers on
the row below, the maximum total from top to bottom is 23.

3
7 4
2 4 6
8 5 9 3

That is, 3 + 7 + 4 + 9 = 23.

Find the maximum total from top to bottom of the triangle below:

75
95 64
17 47 82
18 35 87 10
20 04 82 47 65
19 01 23 75 03 34
88 02 77 73 07 63 67
99 65 04 28 06 16 70 92
41 41 26 56 83 40 80 70 33
41 48 72 33 47 32 37 16 94 29
53 71 44 65 25 43 91 52 97 51 14
70 11 33 28 77 73 17 78 39 68 17 57
91 71 52 38 17 14 91 43 58 50 27 29 48
63 66 04 68 89 53 67 30 73 16 69 87 40 31
04 62 98 27 23 09 70 98 73 93 38 53 60 04 23
"""
import os


def solution():
    """
    Finds the maximum total in a triangle as described by the problem statement
    above.

    >>> solution()
    1074
    """
    script_dir = os.path.dirname(os.path.realpath(__file__))
    triangle = os.path.join(script_dir, "triangle.txt")

    with open(triangle, "r") as f:
        triangle = f.readlines()

    a = [[int(y) for y in x.rstrip("\r\n").split(" ")] for x in triangle]

    for i in range(1, len(a)):
        for j in range(len(a[i])):
            if j != len(a[i - 1]):
                number1 = a[i - 1][j]
            else:
                number1 = 0
            if j > 0:
                number2 = a[i - 1][j - 1]
            else:
                number2 = 0
            a[i][j] += max(number1, number2)
    return max(a[-1])


if __name__ == "__main__":
    print(solution())