From fdac6c60e115297a58f5b81da0c4b7f18ac758f2 Mon Sep 17 00:00:00 2001
From: funemy
Date: Tue, 25 Oct 2022 00:14:40 -0700
Subject: symbolic

---
 entries/funemy/symbolic/phib.py | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 entries/funemy/symbolic/phib.py

(limited to 'entries/funemy/symbolic')

diff --git a/entries/funemy/symbolic/phib.py b/entries/funemy/symbolic/phib.py
new file mode 100644
index 0000000..30d68a8
--- /dev/null
+++ b/entries/funemy/symbolic/phib.py
@@ -0,0 +1,21 @@
+from typing import List
+ 
+def phib(xs: List[int]) -> bool:
+    """
+    Instructions:
+        1. `pip install crosshair-tool`
+        2.  modify the precondition `pre` to control the length of your fib sequence
+        3. run `crosshair check phib.py` in your terminal
+
+    pre: len(xs) >= 10
+    post: __return__ != True
+    """
+    if xs[0] != 0:
+        return False
+    if len(xs) > 1:
+        if xs[1] != 1:
+            return False
+        for i in range(2,len(xs)):
+            if xs[i] != xs[i-1] + xs[i-2]:
+                return False
+        return True
-- 
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