Update fast_fibonacci.py

SandersLin · web-flow · commit 475cdacf736e · 2020-04-18T00:32:34.000+08:00
diff --git a/dynamic_programming/fast_fibonacci.py b/dynamic_programming/fast_fibonacci.py
@@ -8,14 +8,14 @@
 
 
 # returns F(n)
-def fibonacci(n: int):  # noqa: E999 This syntax is Python 3 only
+def fibonacci(n: int) -> int:  # noqa: E999 This syntax is Python 3 only
     if n < 0:
         raise ValueError("Negative arguments are not supported")
     return _fib(n)[0]
 
 
 # returns (F(n), F(n-1))
-def _fib(n: int):  # noqa: E999 This syntax is Python 3 only
+def _fib(n: int) -> int:  # noqa: E999 This syntax is Python 3 only
     if n == 0:
         # (F(0), F(1))
         return (0, 1)
