Day 11 solved.

Made it harder than necessary for myself, but what better
time to screw around with Numpy? Results are surprisingly
ugly, though.

Author: softrabbit

solutions/solution_11.py

@@ -0,0 +1,92 @@
+import sys
+sys.path.append("..")
+
+from aoclib import util
+import numpy as np
+
+# Expand the universe, then find the length of the shortest path
+# between every pair of galaxies. What is the sum of these lengths?
+def solve_11(data):
+    # Expand the universe...
+    universe = np.char.array(data)
+    # ...by inserting empty lines     
+    inserted = 0
+    for i, galaxycount in enumerate(universe.count('#')):
+        if galaxycount == 0:
+               universe = np.insert(universe, i+inserted, '.' * len(universe[i]))
+               inserted += 1
+    
+    # ...and columns
+    universe = np.rot90(universe.view('U1').reshape(universe.size,-1))  
+    inserted = 0
+    for i, line in enumerate(universe):
+        chr,counts = np.unique(line, return_counts=True)
+        counts = dict(zip(chr, counts))
+        if not '#' in counts:             
+             # The axis thing because we now have a 2D array of char...
+             universe = np.insert(universe,i+inserted, line, axis=0)
+             inserted += 1
+
+    tmp = np.where(universe == '#')
+    positions = list(zip(tmp[0],tmp[1]))
+
+    distances = np.zeros((len(positions),len(positions)),dtype=np.int32)
+    # quadratic time, but is there any other way?
+    for i in range(0,len(positions)):
+         for j in range(i+1,len(positions)):
+            # Manhattan distance
+            distances[i][j] = abs(positions[i][0] - positions[j][0]) + abs(positions[i][1] - positions[j][1])
+                    
+
+    print(positions)
+    print(distances)
+
+    print(universe)
+    print(universe.shape)
+    return sum(sum(distances))
+
+# As the first part, but now expand empty rows/columns by one million...
+def solve_11b(data, factor=1000000):    
+    # Expand the universe...
+    universe = np.char.array(data)
+    # ...by inserting empty lines     
+    inserted = 0
+    for i, galaxycount in enumerate(universe.count('#')):
+        if galaxycount == 0:
+               universe = np.insert(universe, i+inserted, '.' * len(universe[i]))
+               inserted += 1
+    
+    # ...and columns
+    universe = np.rot90(universe.view('U1').reshape(universe.size,-1))  
+    inserted = 0
+    for i, line in enumerate(universe):
+        chr,counts = np.unique(line, return_counts=True)
+        counts = dict(zip(chr, counts))
+        if not '#' in counts:             
+             # The axis thing because we now have a 2D array of char...
+             universe = np.insert(universe,i+inserted, line, axis=0)
+             inserted += 1
+
+    tmp = np.where(universe == '#')
+    positions = list(zip(tmp[0],tmp[1]))
+
+    distances = np.zeros((len(positions),len(positions)),dtype=np.int32)
+    # quadratic time, but is there any other way?
+    for i in range(0,len(positions)):
+         for j in range(i+1,len(positions)):
+            # Manhattan distance
+            distances[i][j] = abs(positions[i][0] - positions[j][0]) + abs(positions[i][1] - positions[j][1])
+                    
+
+    print(positions)
+    print(distances)
+
+    print(universe)
+    print(universe.shape)
+    return sum(sum(distances))
+
+
+if __name__ == '__main__':
+    data = util.getInput("../inputs/11.txt")
+    print( solve_11(data) )
+    print( solve_11b(data) )

tests/test_11.py

@@ -0,0 +1,24 @@
+import sys
+sys.path.append("..")
+
+from solutions import solution_11
+
+data = ["...#......",
+".......#..",
+"#.........",
+"..........",
+"......#...",
+".#........",
+".........#",
+"..........",
+".......#..",
+"#...#....."]
+
+
+def test_11():
+    assert solution_11.solve_11(data) == 374
+    
+def test_11b():    
+    assert solution_11.solve_11b(data, 10) == 1030
+    assert solution_11.solve_11b(data, 100) == 8410
+