Migrated from private repo

factorial/factorial.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int factorial(int n) {
+  if (n == 0) {
+    return 1;
+  }
+
+  return n * factorial(n - 1);
+}
+
+int main() {
+  int n;
+  scanf("%d", &n);
+
+  printf("%d\n", factorial(n));
+  return 0;
+}

factorial/factorial.py

@@ -0,0 +1,71 @@
+from manim import *
+config.background_color = (33, 33, 33)
+
+
+class FactorialTree(Scene):
+    # This animation is fundamentally wrong, as it does NOT utilize this type of graph correctly
+    # Still gets the job done though (I think)
+    def construct(self):
+        # Draw the initial node
+        self.bottom = Text(f"factorial(5)", font_size=24, font="Agave Nerd Font Mono").to_edge(DOWN)
+        self.play(Write(self.bottom))
+        self.top_num = 1
+        self.top = Text(f"result = 0", font_size=24, font="Agave Nerd Font Mono").to_edge(UP).to_edge(LEFT)
+        self.last_node = None
+        self.play(Write(self.top))
+        root = self.create_node("5!", position=ORIGIN).to_edge(UP)
+        self.play(FadeIn(root))
+        
+        def drawNode(node, parent, position, right = False):
+            # Draw a multiplication sign in the center between the left and the right node
+            
+            self.bottom.become(Text(f"factorial({n})", font_size=24, font="Agave Nerd Font Mono").to_edge(DOWN))
+            self.play(Indicate(self.bottom))
+
+            self.play(GrowArrow(Arrow(parent.get_bottom(), node.get_top()).scale(0.5)))
+            if final:
+                self.play(Write(Text("x", font_size=24, font="Agave Nerd Font Mono").move_to(position + DOWN * 0.5)))
+                self.last_node = node
+
+            self.play(FadeIn(node))
+            self.play(FadeToColor(node, GREEN))
+
+        # Recursive function to create tree
+        def factorialTree(n, parent, position, level=1):
+            if n <= 0:
+                # Closing animation
+                self.play(FadeToColor(parent, GREEN))
+                self.bottom.become(Text(f"factorial({n})", font_size=24, font="Agave Nerd Font Mono").to_edge(DOWN))
+                self.play(Indicate(self.bottom))
+                return
+
+        
+            # Left child (n-1)!
+            left_pos = position + LEFT + level * DOWN
+            left_child = self.create_node(f"{n-1}!", position=left_pos)
+            
+            drawNode(left_child, parent, position)
+            factorial_tree(n-1, left_child, left_pos, level + 0.3)
+
+            # Funky updates
+            self.top_num *= n
+            self.play(FadeToColor(parent, GREEN))
+
+            # Right child (result of n-1 factorial)
+            right_pos = position + RIGHT + level * DOWN
+            right_child = self.create_node(str(self.top_num), position=right_pos)
+            drawNode(right_child, parent, position, final=True, last=True)
+
+            self.play(Transform(self.top, Text(f"result = {self.top_num}", font_size=24, font="Agave Nerd Font Mono").to_edge(UP).to_edge(LEFT)))
+            
+                
+        # Create the tree
+        factorial_tree(5, root, root.get_center())
+        self.play(Indicate(self.last_node))
+        self.wait(1)
+
+    def create_node(self, content, position):
+        node = Circle().scale(0.25)
+        node_text = Text(content).scale(0.25).move_to(node)
+        node_group = VGroup(node, node_text).move_to(position)
+        return node_group