aoc

commit 3f89885d8fad7f0b12490802a7e9ce3d32b62633 (patch)
parent 1738bec38d6ac146389f1926b6ef835f6f0662bd
Author: Alex Karle <alex@alexkarle.com>
Date:   Sun,  8 Dec 2024 13:58:22 +0100

2024: Add day 8

Diffstat:
A
2024/08/1.py
 | 
43
+++++++++++++++++++++++++++++++++++++++++++
A
2024/08/2.py
 | 
51
+++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 94 insertions(+), 0 deletions(-)
diff --git a/2024/08/1.py b/2024/08/1.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+import sys
+from collections import defaultdict
+
+def parse():
+    ants = defaultdict(list)
+    i = 0;
+    for l in sys.stdin:
+        for j in range(len(l.strip())):
+            c = l[j]
+            if c != '.':
+                ants[c].append((i, j))
+        i += 1
+    return ants, i
+
+def onmap(i, j, n):
+    return i >= 0 and i < n and j >=0 and j < n
+
+def get_anodes(a, b, n):
+    dx = b[1] - a[1]
+    dy = b[0] - a[0]
+    cands = [
+        (b[0] + dy, b[1] + dx),
+        (a[0] - dy, a[1] - dx)
+    ]
+    return filter(lambda x: onmap(x[0], x[1], n), cands)
+
+def count(ants, n):
+    locs = set()
+    for a in ants.keys():
+        nodes = ants[a]
+        # pairwise step through and find new locs
+        for i in range(len(nodes)):
+            for j in range(i + 1, len(nodes)):
+                for l in get_anodes(nodes[i], nodes[j], n):
+                    locs.add(l)
+
+    return len(locs)
+
+if __name__ == '__main__':
+    # input is square nxn
+    ants, n = parse()
+    print(count(ants, n))
diff --git a/2024/08/2.py b/2024/08/2.py
@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+import sys
+from collections import defaultdict
+
+def parse():
+    ants = defaultdict(list)
+    i = 0;
+    for l in sys.stdin:
+        for j in range(len(l.strip())):
+            c = l[j]
+            if c != '.':
+                ants[c].append((i, j))
+        i += 1
+    return ants, i
+
+def onmap(i, j, n):
+    return i >= 0 and i < n and j >=0 and j < n
+
+def get_anodes(a, b, n):
+    dx = b[1] - a[1]
+    dy = b[0] - a[0]
+    anodes = set()
+    for loc in [a, b]:
+        i, j = loc
+        while onmap(i, j, n):
+            anodes.add((i, j))
+            i += dy
+            j += dx
+        i, j = loc
+        while onmap(i, j, n):
+            anodes.add((i, j))
+            i -= dy
+            j -= dx
+    return anodes
+
+def count(ants, n):
+    locs = set()
+    for a in ants.keys():
+        nodes = ants[a]
+        # pairwise step through and find new locs
+        for i in range(len(nodes)):
+            for j in range(i + 1, len(nodes)):
+                for l in get_anodes(nodes[i], nodes[j], n):
+                    locs.add(l)
+
+    return len(locs)
+
+if __name__ == '__main__':
+    # input is square nxn
+    ants, n = parse()
+    print(count(ants, n))