[py] Port 2017_03

py/aoc/y2017/d03.py

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+# 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}")