Day 16 (not super efficient)

2023/day16/code.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+ENERGY = []
+
+
+# direction given as tuple, e.g., (1,0) for right
+def move_beam(x,y,d,grid):
+    while True:
+        if (x > len(grid[0])-1) or (x < 0) or (y > len(grid)-1) or (y < 0): break
+        if d in ENERGY[x+y*len(grid[0])]: break
+        ENERGY[x+y*len(grid[0])].append(d)
+        tile = grid[y][x]
+        if tile == '.':
+            x, y = x+d[0], y+d[1]
+        elif (tile == '-' and d[1] == 0) or (tile == '|' and d[0] == 0):
+            x,y = x+d[0], y+d[1]
+        elif tile == '\\':
+            d = (d[1],d[0])
+            x,y = x+d[0], y+d[1]
+        elif tile == '/':
+            d = (-d[1],-d[0])
+            x,y = x+d[0], y+d[1]
+        elif tile == '-':
+            move_beam(x-1, y, (-1,0), grid)
+            move_beam(x+1, y, (1,0), grid)
+        elif tile == '|':
+            move_beam(x, y-1, (0,-1), grid)
+            move_beam(x, y+1, (0,1), grid)
+
+
+def energize(x,y,d,grid):
+    global ENERGY
+    ENERGY = []
+    for i in range(len(grid) * len(grid[0])):
+        ENERGY.append([])
+    move_beam(x,y,d,grid)
+    return len(ENERGY) - ENERGY.count([])
+
+
+if __name__ == '__main__':
+    grid = [list(line.strip('\n')) for line in open(sys.argv[1])]
+    res2 = 0
+    for i in range(len(grid)):
+        res2 = max(energize(0,i,(1,0),grid),res2)
+    for i in range(len(grid[0])):
+        res2 = max(energize(i,0,(0,1),grid),res2)
+    for i in range(len(grid)):
+        res2 = max(energize(len(grid)-1,i,(-1,0),grid),res2)
+    for i in range(len(grid[0])):
+        res2 = max(energize(i,len(grid[0])-1,(0,-1),grid),res2)
+
+    # challenge 1
+    res1 = str(energize(0,0,(1,0),grid))
+    print(f"challenge 1:\n{res1}\n")
+
+    # challenge 2
+    res2 = str(res2)
+    print(f"challenge 2:\n{res2}\n")
+