From b5b18e46e3a5c4daaa3b4613395b1a216a47bc17 Mon Sep 17 00:00:00 2001
From: braxtonhall
Date: Sun, 23 Oct 2022 11:20:39 -0700
Subject: Initial commit

---
 entries/braxtonh/types/index.ts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 entries/braxtonh/types/index.ts

(limited to 'entries/braxtonh/types/index.ts')

diff --git a/entries/braxtonh/types/index.ts b/entries/braxtonh/types/index.ts
new file mode 100644
index 0000000..11f4086
--- /dev/null
+++ b/entries/braxtonh/types/index.ts
@@ -0,0 +1,18 @@
+type Zero = "😰";
+
+type Succ<N> = {prev: N};
+
+type Prev<N> = N extends Succ<infer P> ? P : never;
+
+type Add<A, B> = B extends Zero ? A : Succ<Add<A, Prev<B>>>;
+
+type _Fib<N, AccumulatorA, AccumulatorB> =
+	N extends Zero
+		? AccumulatorA
+		: N extends Succ<Zero>
+			? AccumulatorB
+			: _Fib<Prev<N>, AccumulatorB, Add<AccumulatorA, AccumulatorB>>;
+
+type Fib<N> = _Fib<N, Zero, Succ<Zero>>;
+
+export type {Zero, Succ, Fib};
-- 
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