Add solution for day 10

src/day10.py

@@ -0,0 +1,103 @@
+#!/usr/bin/env python3
+
+from util import print_color, read_input, Color
+
+
+cardinals = [
+    # up
+    lambda row, col: (row - 1, col),
+    # down
+    lambda row, col: (row + 1, col),
+    # left
+    lambda row, col: (row, col - 1),
+    # right
+    lambda row, col: (row, col + 1),
+]
+
+
+def find_next(grid, cur_row, cur_col):
+    current_value = grid[cur_row][cur_col]
+    if not current_value.isdigit():
+        return []
+    current_value = int(current_value)
+    if current_value == 9:
+        return [(cur_row, cur_col)]
+    nines = []
+    for cardinal in cardinals:
+        (new_row, new_col) = cardinal(cur_row, cur_col)
+        if new_row < 0 or new_col < 0 or new_row >= len(grid) or new_col >= len(grid[0]):
+            continue
+        next_value = grid[new_row][new_col]
+        if not next_value.isdigit():
+            continue
+        next_value = int(next_value)
+        if next_value == current_value + 1:
+            nines.extend(find_next(grid, new_row, new_col))
+    return nines
+
+
+def part1(input_lines):
+    zeroes = []
+    for row, line in enumerate(input_lines):
+        for col, char in enumerate(line):
+            if input_lines[row][col] == '0':
+                zeroes.append((row, col))
+    complete_trails = set()
+    for zero in zeroes:
+        for complete_trail in find_next(input_lines, zero[0], zero[1]):
+            complete_trails.add((zero, complete_trail))
+
+    return len(complete_trails)
+
+
+def part2(input_lines):
+    zeroes = []
+    for row, line in enumerate(input_lines):
+        for col, char in enumerate(line):
+            if input_lines[row][col] == '0':
+                zeroes.append((row, col))
+    complete_trails = []
+    for zero in zeroes:
+        for complete_trail in find_next(input_lines, zero[0], zero[1]):
+            complete_trails.append((zero, complete_trail))
+
+    return len(complete_trails)
+
+
+test_input = read_input("_test")
+test_input_result = part1(test_input)
+print_color(test_input_result, Color.GREY)
+assert 1 == test_input_result
+
+test_input = read_input("_test_2")
+test_input_result = part1(test_input)
+print_color(test_input_result, Color.GREY)
+assert 2 == test_input_result
+
+test_input = read_input("_test_3")
+test_input_result = part1(test_input)
+print_color(test_input_result, Color.GREY)
+assert 4 == test_input_result
+
+test_input = read_input("_test_4")
+test_input_result = part1(test_input)
+print_color(test_input_result, Color.GREY)
+assert 3 == test_input_result
+
+test_input = read_input("_test_5")
+test_input_result = part1(test_input)
+print_color(test_input_result, Color.GREY)
+assert 36 == test_input_result
+
+real_input = read_input()
+print(part1(real_input))
+
+test_input = read_input("_test_6")
+test_input_result = part2(test_input)
+print_color(test_input_result, Color.GREY)
+assert 3 == test_input_result
+
+test_input = read_input("_test_5")
+test_input_result = part2(test_input)
+assert 81 == test_input_result
+print(part2(real_input))