Summed Area Table solution for 2018 Day 11

2018/day11-cleaned.py

@@ -0,0 +1,48 @@
+import numpy as np
+input = 4455
+fuel_cells = np.zeros((301,301), dtype=np.int64)
+
+for y in range(1, 301):
+  fuel_cells[1:,y] = y
+for x in range(1, 301):
+  fuel_cells[x,1:] *= x+10
+fuel_cells[1:,1:] += input
+for x in range(1, 301):
+  fuel_cells[x,1:] *= x+10
+fuel_cells[1:,1:] //= 100
+fuel_cells[1:,1:] %= 10
+fuel_cells[1:,1:] -= 5
+fuel_cs = fuel_cells.cumsum(axis=0).cumsum(axis=1)
+
+
+def sum_square(x, y, s):
+  A = fuel_cs[x-1, y-1]
+  B = fuel_cs[x+s-1, y-1]
+  C = fuel_cs[x-1, y+s-1]
+  D = fuel_cs[x+s-1, y+s-1]
+  return D - B - C + A
+
+
+max_power_3 = 0
+max_idx_3 = (0, 0, 0)
+for x in range(1, 299):
+  for y in range(1, 299):
+    val = sum_square(x, y, 3)
+    if val > max_power_3:
+      max_power_3 = val
+      max_idx_3 = (x, y, 3)
+
+print(max_idx_3)  # Part 1
+
+
+max_power_s = 0
+max_idx_s = (0,0,0)
+for x in range(1, 298):
+  for y in range(1, 298):
+    for s in range(4, 302-max(x, y)):
+      val = sum_square(x, y, s)
+      if val > max_power_s:
+        max_power_s = val
+        max_idx_s = (x, y, s)
+
+print(max_idx_s)  # Part 2