added fibonacci_search.py (#1341)

* added fibonacci_search.py

* added Fibonacci_search.py after error handling

* added doctests

Author: laishawadhwa

searches/fibonacci_search.py

@@ -0,0 +1,50 @@
+#run using python fibonacci_search.py -v
+
+'''
+@params
+arr: input array
+val: the value to be searched
+output: the index of element in the array or -1 if not found
+return 0 if input array is empty
+'''
+def fibonacci_search(arr, val):
+
+    """
+    >>> fibonacci_search([1,6,7,0,0,0], 6)
+    1
+    >>> fibonacci_search([1,-1, 5, 2, 9], 10)
+    -1
+    >>> fibonacci_search([], 9)
+    0
+    """
+    fib_N_2 = 0
+    fib_N_1 = 1
+    fibNext = fib_N_1 + fib_N_2
+    length = len(arr)
+    if length == 0:
+    	return 0
+    while (fibNext < len(arr)):
+        fib_N_2 = fib_N_1
+        fib_N_1 = fibNext
+        fibNext = fib_N_1 + fib_N_2
+    index = -1;
+    while (fibNext > 1):
+        i = min(index + fib_N_2, (length-1))
+        if (arr[i] < val):
+            fibNext = fib_N_1
+            fib_N_1 = fib_N_2
+            fib_N_2 = fibNext - fib_N_1
+            index = i
+        elif (arr[i] > val):
+            fibNext = fib_N_2
+            fib_N_1 = fib_N_1 - fib_N_2
+            fib_N_2 = fibNext - fib_N_1
+        else :
+            return i
+    if (fib_N_1 and index < length-1) and (arr[index+1] == val):
+        return index+1;
+    return -1
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod()