recursion/fibonacci

Author: ivanmmarkovic

recursion/fibonacci-iterative.py

@@ -0,0 +1,14 @@
+def fibonacci(n: int) -> int:
+    if n <= 1:
+        return 0
+    elif n == 2:
+        return 1
+    prev: int = 0
+    curr: int = 1
+    for _ in range(n - 2):
+        prev, curr = curr, prev + curr
+    return curr
+
+
+for i in range(6):
+    print(fibonacci(i))

recursion/fibonacci-memoization.py

@@ -0,0 +1,18 @@
+
+nums: dict = {}
+
+
+def fibonacci(n: int) -> int:
+    if n <= 1:
+        return 0
+    elif n == 2:
+        return 1
+    else:
+        if n in nums:
+            return nums[n]
+        nums[n] = fibonacci(n - 1) + fibonacci(n - 2)
+        return nums[n]
+
+
+for i in range(6):
+    print(fibonacci(i))

recursion/fibonacci-recursive-worst-solution.py

@@ -0,0 +1,11 @@
+def fibonacci(n: int) -> int:
+    if n <= 1:
+        return 0
+    elif n == 2:
+        return 1
+    else:
+        return fibonacci(n - 1) + fibonacci(n - 2)
+
+
+for i in range(6):
+    print(fibonacci(i))

recursion/fibonacci-recursive.py

@@ -0,0 +1,15 @@
+def fibonacci(n: int) -> int:
+
+    def fibonacci_helper(num: int, prev: int = 0, curr: int = 1) -> int:
+        if num <= 1:
+            return prev
+        elif num == 2:
+            return curr
+        else:
+            return fibonacci_helper(num - 1, curr, prev + curr)
+
+    return fibonacci_helper(n)
+
+
+for i in range(6):
+    print(fibonacci(i))