edit solution of 509

Author: RexWzh

src/problems/509.fibonacci-number.jl

@@ -60,7 +60,13 @@
 ## @lc code=start
 using LeetCode
 
-function fib(n::Int)
-    [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040][n]
+function fib(n::Int)::Int
+    n <= 1 && return n
+    pre, cur = 0, 1
+    for _ in 2:n
+        pre, cur = cur, pre + cur
+    end
+    return cur
 end
+
 ## @lc code=end

test/problems/509.fibonacci-number.jl

@@ -1,3 +1,3 @@
 @testset "509.fibonacci-number.jl" begin
-    @test fib(5) == 5
+    @test fib.(0:10) == [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
 end