Problem 18

p18.py

def top_to_bottom(tri):
    for i in range(1,len(tri)):
        a = len(triangle[i])
        for j in range(0, a):
            if j == 0:
                tri[i][j] += tri[i-1][j]
            elif j == a-1:
                tri[i][j] += tri[i-1][j-1]
            else:
                tri[i][j] += max(tri[i-1][j],tri[i-1][j-1])
    return max(tri[-1])
  
def bottom_to_top(tri):
    for i in reversed(range(len(triangle) - 1)):
        for j in range(len(triangle[i])):
            if triangle[i + 1][j] >= triangle[i + 1][j + 1]:
                triangle[i][j] += triangle[i + 1][j]
            else:
                triangle[i][j] += triangle[i + 1][j + 1]
    return triangle[0][0]