day12: add solutions

Author: tfaughnan

day12/1.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env pypy3
+
+import sys
+from collections import deque
+
+def edges(graph, coord):
+    r, c = coord
+    return (n for n in ((r - 1, c), (r + 1, c), (r, c - 1), (r, c + 1))
+            if n in graph and graph[n] - graph[coord] <= 1)
+
+def main():
+    graph = {}
+    start = None
+    end = None
+    for r, line in enumerate(sys.stdin):
+        for c, char in enumerate(line.strip()):
+            if char == 'S':
+                start = (r, c)
+                graph[(r, c)] = ord('a')
+            elif char == 'E':
+                end = (r, c)
+                graph[(r, c)] = ord('z')
+            else:
+                graph[(r, c)] = ord(char)
+
+    steps = shortest_path(graph, start, end)
+    print(steps)
+
+def shortest_path(graph, start, end):
+    to_explore = deque([(start, 0)])
+    explored = set()
+    while to_explore:
+        here, steps = to_explore.popleft()
+        if here == end:
+            return steps
+        for neighbor in edges(graph, here):
+            if neighbor not in explored:
+                explored.add(neighbor)
+                to_explore.append((neighbor, steps + 1))
+
+    raise ValueError('No paths exist!')
+
+if __name__ == '__main__':
+    main()

day12/2.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env pypy3
+
+import sys
+from collections import deque
+
+# searching backwards, so reverse check
+def edges(graph, coord):
+    r, c = coord
+    return (n for n in ((r - 1, c), (r + 1, c), (r, c - 1), (r, c + 1))
+            if n in graph and graph[coord] - graph[n] <= 1)
+
+def main():
+    graph = {}
+    end = None
+    for r, line in enumerate(sys.stdin):
+        for c, char in enumerate(line.strip()):
+            if char == 'S':
+                graph[(r, c)] = ord('a')
+            elif char == 'E':
+                end = (r, c)
+                graph[(r, c)] = ord('z')
+            else:
+                graph[(r, c)] = ord(char)
+
+    steps = shortest_path_to_height(graph, end, ord('a'))
+    print(steps)
+
+def shortest_path_to_height(graph, start, height):
+    to_explore = deque([(start, 0)])
+    explored = set()
+    while to_explore:
+        here, steps = to_explore.popleft()
+        if graph[here] == height:
+            return steps
+        for neighbor in edges(graph, here):
+            if neighbor not in explored:
+                explored.add(neighbor)
+                to_explore.append((neighbor, steps + 1))
+
+    raise ValueError('No paths exist!')
+
+if __name__ == '__main__':
+    main()

day12/input.txt

@@ -0,0 +1,41 @@
+abaaaaacccccccccccccccccccccccccccccccccccccccaaaaaaaccccaaaaaaaaaaaaaaaaacccccaaaaaacccccccccccccccccccccccaaaaaaaaccccccccccccccccccccccccccccccccaaaaaa
+abaaaaaacccaaaacccccccccccccccccccccccaccccccccaaaaaaaaccaaaaaaaaaaaaaaaaccccccaaaaaacccccccccccccccccccccccccaaaaccccccccccccccccccccccccccccccccccaaaaaa
+abaaaaaacccaaaacccccccccccccccccaaaaaaaacccccccaaaaaaaaacaaaaaaaaaaaaacccccccccaaaaacccccccccccccccccccccccccaaaaacccccccccccccccccccaaaccccccccccccaaaaaa
+abaaacaccccaaaaccccccccccccccccccaaaaaacccccccccaaaaaaaccccaaaaaaaaaaacccccccccaaaaacccccccccccccccccccccccccaacaaaccccccccccccccccccaaacccccccccccccccaaa
+abaaacccccccaaacccccccccccaacccccaaaaaaccccccccaaaaaaccccccaacaaaaaaaacccccccccccccccccccccccaaccccccccccccccacccaaaaacccccccccaaccccaaacccccccccccccccaaa
+abccccccccccccccccccccccccaaaaccaaaaaaaacccccccaaaaaaaccccccccaaaaaaaaaccccccccccaacccccccccaaaccccccccccccccccccacaaacccccccccaaaaccaaacccccccccccccccaac
+abccccccccccccccccccccccaaaaaacaaaaaaaaaaccccccaaccaaaaacccccaaaaccaaaaccccccccccaaacaacccccaaacaaacccaaccccccccaaaaaaaacccccccaaaaakkkkkkcccccccccccccccc
+abccccccccccccccccccccccaaaaaccaaaaaaaaaacccccccccccaaaaaaccccacccaaaaaccccccccccaaaaaaccaaaaaaaaaaaaaaaccccccccaaaaaaaaccccccccaaajkkkkkkkaccccccaacccccc
+abcccccccccccccccccccccccaaaaacacacaaaccccccccccccccaaaaaaccccccccaaaacccccccccaaaaaaacccaaaaaaaaaaaaaaaaaccccccccaaaaaccccccccccjjjkkkkkkkkccaaaaaacccccc
+abcccccccccccccccccccccccaacaacccccaaacccaccccccccccaaaaaaccccccccaaaacccccccccaaaaaaacccccaaaaaacaaaaaaaacccccccaaaaacccccccjjjjjjjooopppkkkcaaaaaaaccccc
+abcccccccccccccccccaacaacccccccccccaaaaaaacccccccccccaaaaacccccccccccccccccccccccaaaaaaccccaaaaaaccaaaaaaacccccccaaaaaacciijjjjjjjjoooopppkkkcaaaaaaaacccc
+abccccccccccaaaccccaaaaacccccccccccccaaaaacccccccccccaaaaccccccccccccccccccccccccaacaaaccccaaaaaaacaaaaacccccccccaccaaaciiiijjjjjjoooopppppkllcaaaaaaacccc
+abccaaccccccaaaaacaaaaacccccccccccccaaaaaacccccccccccccccccccccccccccccccccccccccaacccccccaaaacaaaaaaaaacccaaccccaaaaaciiiiinoooooooouuuupplllaaaaaacccccc
+abcaaacccccaaaaaacaaaaaacccccccccccaaaaaaaaccccccccaacaccccccccccccccccccccccccccccccccccccaccccccccccaaccaaaccccaaaaaciiinnnooooooouuuuuppplllaaacacccccc
+abaaaaaacccaaaaaacccaaaacccccccccccaaaaaaaaccccccccaaaaccccccccccccccccccccccccccccccccccccccccccccccccaaaaacaacaaaaaaiiinnnnntttoouuuuuupppllllcccccccccc
+abaaaaaaccccaaaaacccaaccccccccccacccccaaccccccccccaaaaaccccccccccccccccccccccccccccccccccccccccccccccccaaaaaaaacaaaaaaiiinnnnttttuuuuxxuuupppllllccccccccc
+abaaaaacccccaacaaccccccccccccccaaaccccaacccccaacccaaaaaacccccccccccccccccccccccccccccccccccccccccccccccccaaaaaccaaaaaaiiinnnttttxxuuxxyyuuppppllllcccccccc
+abaaaacccccccccccccccccccccaaacaaaccccccaaacaaaaccacaaaacccccccccccccccccccccccccccccccccccaacccccccccccaaaaaccccaaaccciinnntttxxxxxxxyyvvvqqqqqlllccccccc
+abaaaaaccccccccccccccccccccaaaaaaaaaacccaaaaaaacccccaaccccccccccccccccccccccccccccccccccccaaacccccccccccaacaaaccccccccciiinntttxxxxxxxyyvvvvvqqqqljjcccccc
+abccaaaccaccccccccaaacccccccaaaaaaaaaccccaaaaaacccccccccccccccccccccccccccccccaacccccccaaaaacaaccccccccccccaacccccccccchhinnnttxxxxxxyyyyyvvvvqqqjjjcccccc
+SbccccaaaacccccccaaaaaacccccccaaaaaccccccaaaaaaaaccccccccccccccccccccaaccccccaaaaccccccaaaaaaaacccccccccccccccccccccccchhhnnntttxxxxEzyyyyyvvvqqqjjjcccccc
+abccccaaaacccccccaaaaaaccccccaaaaaacccccaaaaaaaaaacccccccccccccccccccaaccccccaaaaccccccccaaaaacccccccccccccccccccccccccchhhnntttxxxyyyyyyyvvvvqqqjjjcccccc
+abcccaaaaaaccccccaaaaaacccccaaaaaaaccccaaaaaaaaaacccccccccccccccccaaaaaaaacccaaaacccccccaaaaaccccccccccccccccccccccccccchhmmmttxxxyyyyyyvvvvvqqqjjjdcccccc
+abcccaaaaaacccccccaaaaacccccaaacaaacaaaaaaaaaaccccccccccccaaacccccaaaaaaaaccccccccccccccaacaaacccccccaacaaacccccccccccchhhmmmtswwwyyyyyyvvvqqqqjjjjdddcccc
+abcccccaacccccccccaacaacccccccccccacaaaaaccaaaccccccccccaaaaacccccccaaaacccccccccccccccccccaaccccccccaaaaaacccccccccccchhhmmssswwwwwwyyywvrqqqjjjjdddccccc
+abcccccccccccccccccccccccccccccccccaaaaaccccaaccccccccacaaaaaacccccaaaaacccccccccccccccccccccccccccccaaaaaacccccccccccchhhmmssswwwwwwywywwrrqjjjjddddccccc
+abcccccccccccccccccccccccccccccccccaaaaaccccccccaaacaaacaaaaaacccccaaaaaaccccccccccccccccccccccccccccaaaaaaaccccccccccchhmmmsssswwsswwwwwwrrkkjjddddcccccc
+abccccccccccccccccccccccccccccccccccaaaaacccccccaaaaaaacaaaaaccccccaaccaacccccccccccaaccccccccccccccaaaaaaaacaacaaccccchhhmmmsssssssswwwwrrrkkjddddaaccccc
+abcccccccccccccccccccccccccaaaaaccccaacccccccccccaaaaaacaaaaacccccccccccccaacccccccaaaaaacccccccccccaaaaaaaacaaaaaccccchhgmmmmssssssrrwwwrrrkkddddaaaccccc
+abcccccccccccccccccccccccccaaaaacccccccccccccccccaaaaaaaacccccccccccccccaaaaaaccccccaaaaaccccaaccccccccaaacccaaaaaaccccgggmmmmmmllllrrrrrrrkkkeedaaaaccccc
+abcccccccccccaaccccccccccccaaaaaacccccccccccccccaaaaaaaaacccccccccccccccaaaaaaccccaaaaaaacccaaaacccccccaaccccaaaaaaccccggggmmmmllllllrrrrrkkkkeedaaaaacccc
+abcccccccccccaaacaacaaaccccaaaaaaccccccccccccccaaaaaaaaaacccccccccccccccaaaaaaccccaaaaaaaaccaaaacccccccccccccaaaaaccccccgggggglllllllllrrkkkkeeeaaaaaacccc
+abcccccccccccaaaaaacaaaacccaaaaaaccccccccccccccaaacaaaaaaccccccccccccccccaaaaaccccaaaaaaaaccaaaacccccccccccaaccaaaccccccgggggggggffflllkkkkkkeeeaaaaaacccc
+abaccccccccaaaaaaaccaaaacccccaaacccccccccccccccccccaaaaaacaccccccccaaccccaaaacccccccaaacacccccccccccccccaaaaaccccccccccccccgggggffffflllkkkkeeeccaaacccccc
+abaccccccccaaaaaaaccaaacccccccccccccccccaaaccccccccaaacaaaaaccccccaaacccccccccccccaaaacccccccccccccccccccaaaaaccccccccccccccccccaffffffkkkeeeeeccaaccccccc
+abaaaccccccccaaaaaaccccccccccccccccccccaaaaaacccccccaaaaaaaacaaaacaaacccccccccaaaaaacccccccccccccccccccccaaaaaccccccccccccccccccccaffffffeeeeecccccccccccc
+abaacccccccccaacaaaccccccccccccccccccccaaaaaaccccccccaaaaaccaaaaaaaaacccccccccaaaaaaaaccccccccccaaccccccaaaaacccccccccccccccccccccaaaffffeeeecccccccccccaa
+abaacccccccccaaccccccccccccccccaaccccccaaaaacaaccaacccaaaaacaaaaaaaaacccccccccaaaaaaaaccccccaaacaacccccccccaacccccccccccccccccccccaaaccceaecccccccccccccaa
+abaacccccccccccccccccccccccccccaaaaaacccaaaaaaaaaaaccaaacaaccaaaaaaaaaaaaacccccaaaaaaacccccccaaaaaccccccccccccccccccccccccccccccccaaacccccccccccccccaaacaa
+abcccccccccccccccccccccccccccccaaaaaccccaacaacaaaaacccaaccccccaaaaaaaaaaaacccccaaaaacccccccccaaaaaaaccccccccccccccccccccccccccccccaaacccccccccccccccaaaaaa
+abcccccccccccccccccccccccccccaaaaaaaccccccccaaaaaaaaccccccccccaaaaaaaaaaccccccaaaaaaccccccccaaaaaaaaccccccccccccccccccccccccccccccccccccccccccccccccaaaaaa

day12/sample.txt

@@ -0,0 +1,5 @@
+Sabqponm
+abcryxxl
+accszExk
+acctuvwj
+abdefghi