some function of fibonacci sque

fib/fib01.py

@@ -0,0 +1,14 @@
+#!/usr/bin/env python
+# coding=utf-8
+
+def fib(n):
+    if n == 0:
+        return 0
+    elif n == 1:
+        return 1
+    else:
+        return fib(n-1) + fib(n-2)
+
+if __name__=="__main__":
+    n = fib(4)
+    print(n)

fib/fib02.py

@@ -0,0 +1,11 @@
+#!/usr/bin/env python
+# utf-8
+
+from math import sqrt
+
+def fib(n):
+    return ((1+sqrt(5))**n - (1-sqrt(5))**n)/(2**n*sqrt(5))
+
+if __name__=="__main__":
+    f = fib(4)
+    print(f)

fib/fib03.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+# utf-8
+
+def fib(n):
+    f = [0, 1]
+    for i in range(n-2):
+        f.append(f[-2] + f[-1])
+    return f
+
+if __name__ == "__main__":
+    lst = fib(4)
+    print(lst)

fib/fib04.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+#utf-8
+
+def fib(n):
+    a, b = 0, 1
+    while n > 0:
+        a, b = b, a + b
+        n -= 1
+    return a
+
+if __name__ == "__main__":
+    print(fib(4))