96 lines
2.8 KiB
Python
96 lines
2.8 KiB
Python
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from manim import *
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config.background_color = (33, 33, 33)
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INPUT = "PFISAWESOME" # Manim does not like spaces unfortunately
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class StringReversal(Scene):
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def construct(self):
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# Big string
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self.string = Text(INPUT, font_size=64, font="Agave Nerd Font Mono")
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# Intro animation
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self.play(Write(self.string))
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self.bottom = Text(f"reverse({self.string.text}, start=0, end={len(self.string)-1})", font_size=24, font="Agave Nerd Font Mono")
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self.bottom.to_edge(DOWN).to_edge(LEFT)
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self.play(Write(self.bottom))
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# Call the recursive function
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result = self.reverse(INPUT, 0, len(INPUT) - 1)
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# Outro animation
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self.play(Unwrite(self.bottom))
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self.play(FadeToColor(self.string, GREEN))
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self.wait(4)
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self.play(Unwrite(self.string))
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self.wait(1)
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def bottom_text(self, text):
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# Update the bottom text
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self.play(
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Transform(
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self.bottom,
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Text(
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text,
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font_size=24,
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font="Agave Nerd Font Mono"
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).to_edge(DOWN).to_edge(LEFT)
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)
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)
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self.wait(1)
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# Visual swap
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def swap_chars(self, counter):
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# Indicate the characters we're about to swap
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self.play(
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Indicate(self.string[counter]),
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Indicate(self.string[len(self.string) - counter - 1])
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)
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self.wait(.5)
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# Swap the characters
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self.play(
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Swap(
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self.string[counter],
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self.string[len(self.string) - counter - 1]
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)
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)
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self.wait(1)
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def reverse(self, string, start, end, counter=0):
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# Color the characters that we're about to swap in bottom text
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self.bottom_text(f"reverse({string}, start={start}, end={end})")
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# Base case: If we've reached the middle of the string
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if start >= end:
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self.play(FadeToColor(self.bottom, GREEN))
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self.play(Unwrite(self.bottom))
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# There must be a way to set defaults for text
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success = Text(
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"We reached the base case!",
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font_size=24,
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font="Agave Nerd Font Mono"
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).to_edge(DOWN).to_edge(LEFT)
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self.play(Write(success))
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self.wait(1)
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self.play(Unwrite(success))
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return string
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# Swap first and last chars of string
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string = list(string)
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string[start], string[end] = string[end], string[start]
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string = "".join(string)
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self.swap_chars(counter)
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counter += 1
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# Recursively call reverse on the substring
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self.reverse(string, start + 1, end - 1, counter)
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