Advent of Code is a coding challenge that releases a puzzle every day starting December 1st up until the 25th - like an Advent Calendar but no stale chocolate...

Part 1

Given a 2D, repeating map of 'trees' and snow find how many trees you will hit with a slope of 3 right, 1 down starting from the top left corner.

Solution:

                                
                                    
    import csv
    
    def get_panel(file_name):
        panel = []
        with open(file_name, 'r') as data:
            reader = csv.reader(data)
            for line in reader:
                panel.append(list(line[0]))
    
        return panel
    
    
    def print_panel(panel):
        print('\n'.join(map(lambda l: ''.join(l), panel)))
    
    
    def count_trees(panel, step_h, step_w):
        panel_h = len(panel)
        panel_w = len(panel[0])
    
        index_h = 0
        index_w = 0
    
        tree_count = 0
    
        while index_h < panel_h - step_h:
            index_h += step_h
            index_w += step_w
    
            if index_w >= panel_w:
                index_w = index_w - panel_w
    
            xo = panel[index_h][index_w]
    
            if xo == '#':
                tree_count += 1
    
        return tree_count
    
    
    panel = get_panel('__03.txt')
    trees = count_trees(panel, 1, 3)
    print('TREES: ', trees)
        
                                
                            

Part 2

Find how many trees you would hit for the following slopes: Right 1, down 1. Right 3, down 1. (This is the slope you already checked.) Right 5, down 1. Right 7, down 1. Right 1, down 2.

Solution:

                                
                                    
    slopes = [(1,1), (1,3), (1,5), (1,7), (2,1)]
    tree_count = map(lambda x: count_trees(panel, x[0], x[1]), slopes)
    print(tree_count)
    print(reduce(lambda x, y: x*y, tree_count))
        
                                
                            

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