[py] Port 2017_03

py/aoc/__init__.py

@@ -2,7 +2,7 @@ import sys
 import argparse
 from pathlib import Path
 
-from .y2017 import d01, d02
+from .y2017 import d01, d02, d03
 from .y2018 import d01, d02, d03, d04, d05, d06, d07, d08, d09, d10, d11
 from .y2020 import d10
 from .y2021 import d14
@@ -11,6 +11,7 @@ from .y2022 import d01, d02, d03, d04, d05, d06
 DAYS = {
     "2017_01": y2017.d01.solve,
     "2017_02": y2017.d02.solve,
+    "2017_03": y2017.d03.solve,
     "2018_01": y2018.d01.solve,
     "2018_02": y2018.d02.solve,
     "2018_03": y2018.d03.solve,

py/aoc/y2017/d03.py

@@ -0,0 +1,67 @@
+# PART 1
+
+
+def spiral(nth):
+    length = 1
+    nth -= 1
+    x = 0
+    y = 0
+    while True:
+        x += min(length, nth)
+        nth -= min(length, nth)
+        if nth == 0:
+            return x, y
+        y += min(length, nth)
+        nth -= min(length, nth)
+        if nth == 0:
+            return x, y
+
+        length += 1
+
+        x -= min(length, nth)
+        nth -= min(length, nth)
+        if nth == 0:
+            return x, y
+        y -= min(length, nth)
+        nth -= min(length, nth)
+        if nth == 0:
+            return x, y
+
+        length += 1
+
+
+def manhattan(x, y):
+    return abs(x) + abs(y)
+
+
+# PART 2
+
+
+def store(cap):
+    stored = {(0, 0): 1}
+    nth = 2
+    while True:
+        x, y = spiral(nth)
+        adjacent = 0
+        adjacent += stored.get((x - 1, y - 1), 0)
+        adjacent += stored.get((x, y - 1), 0)
+        adjacent += stored.get((x + 1, y - 1), 0)
+        adjacent += stored.get((x - 1, y), 0)
+        adjacent += stored.get((x + 1, y), 0)
+        adjacent += stored.get((x - 1, y + 1), 0)
+        adjacent += stored.get((x, y + 1), 0)
+        adjacent += stored.get((x + 1, y + 1), 0)
+        stored[(x, y)] = adjacent
+        nth += 1
+
+        if adjacent > cap:
+            return adjacent
+
+
+def solve(inputstr):
+    nth = int(inputstr.strip())
+    x, y = spiral(nth)
+    dist = manhattan(x, y)
+    print(f"Part 1: {dist}")
+    adjacent = store(nth)
+    print(f"Part 2: {adjacent}")