1 files changed, 33 insertions, 0 deletions
diff --git a/2021/13.py b/2021/13.py
new file mode 100644
index 0000000..d5b0765
--- /dev/null
+++ b/2021/13.py
@@ -0,0 +1,33 @@
+# Day Thirteen: Transparent Origami
+
+file = open("input/13.txt").readlines()
+
+def fold(paper: set, axis: str, crease: int) -> set:
+    result = set()
+    for dot in paper:
+        if axis == "x" and dot[0] >= crease:
+            result.add((crease - (dot[0] - crease), dot[1]))
+        elif axis == "y" and dot[1] >= crease:
+            result.add((dot[0], crease - (dot[1] - crease)))
+        else:
+            result.add(dot)
+    return result
+
+paper = set()
+for i, line in enumerate(file):
+    if i < 1125: # Hardcoded for simplicity
+        x, y = map(int, line.strip().split(","))
+        dot = (x, y)
+        paper.add(dot)
+    elif i > 1125:
+        ins = line.split()[2].split("=")
+        paper = fold(paper, ins[0], int(ins[1]))
+        if i == 1126: print(len(paper))
+
+for i in range(6):
+    for j in range(39):
+        if (j, i) in paper:
+            print("#", end="")
+        else:
+            print(" ", end="")
+    print()