project-euler/Sidef/067 Maximum path sum II.sf

#!/usr/bin/ruby

# Author: Daniel "Trizen" Șuteu
# License: GPLv3
# Website: https://github.com/trizen

# Find the maximum total from top to bottom in triangle.txt, a 15K text file containing a triangle with one-hundred rows.

# https://projecteuler.net/problem=67

# Runtime: 0.273s

var data = %f'p067_triangle.txt'.read
var triangle = data.lines.map{.words.map{.to_i}}

var sum = [0]

triangle.each { |x|
    sum = [
            x[0] + sum[0],
            {|i| x[i] + max(sum[i-1, i]) }.map(1 ..^ x.end)...,
            x[-1] + sum[-1],
          ]
}

say sum.max