Day 15

day15/part1.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+import heapq
+
+import numpy as np
+
+arr = np.array([[int(n) for n in line.strip()] for line in open("input.txt")])
+arr = np.pad(arr, (1, 1), 'constant', constant_values=(9999,))
+
+open_list = [(arr[1, 1], (1, 1))]
+closed_list = np.zeros_like(arr)
+target = arr[:-2, :-2].shape
+
+while len(open_list):
+    val, (y, x) = heapq.heappop(open_list)
+    if (y, x) == target:
+        print(val - arr[1, 1])
+        break
+    if closed_list[y, x] != 0:
+        continue
+    closed_list[y, x] = val
+    for yn, xn in [(1, 0), (-1, 0), (0, 1), (0, -1)]:
+        if closed_list[y+yn, x+xn] == 0:
+            heapq.heappush(open_list, (arr[y+yn, x+xn]+val, (y+yn, x+xn)))
+
+print(np.sum(closed_list[1:-1, 1:-1] != 0), arr[1:-1, 1:-1].shape[0]*arr[1:-1, 1:-1].shape[1])