Added implementation of ternary search

Author: OmkarPathak

pygorithm/searching/__init__.py

@@ -4,15 +4,19 @@
 from . import binary_search
 from . import breadth_first_search
 from . import depth_first_search
+from . import exponential_search
 from . import interpolation_search
 from . import linear_search
 from . import quick_select
+from . import ternary_search
 
 __all__ = [
     'binary_search',
     'breadth_first_search',
     'depth_first_search',
+    'exponential_search',
     'interpolation_search',
     'linear_search',
-    'quick_select'
+    'quick_select',
+    'ternary_search'
 ]

pygorithm/searching/ternary_search.py

@@ -0,0 +1,53 @@
+'''
+Author: OMKAR PATHAK
+Created at: 26th August 2017
+
+Time complexity: O(logn)
+
+More Info: https://en.wikipedia.org/wiki/Ternary_search
+'''
+from __future__ import division
+import inspect
+
+def search(_list, left, right, target):
+    if right >= left:
+        mid1 = (left + right) // 3
+        mid2 = (mid1 + right) // 3
+
+        # if target is present at mid1
+        if _list[mid1] == target:
+            return mid1
+
+        # if target is present at mid2
+        if _list[mid2] == target:
+            return mid2
+
+        # if target is present at left one-third
+        if _list[mid1] > target:
+            return search(_list, left, mid1 - 1, target)
+
+        # if target is present at right one-third
+        if _list[mid2] < target:
+            return search(_list, mid2 + 1, right, target)
+
+        # if target is present in the middle one-third
+        return search(_list, mid1 + 1, mid2 - 1, target)
+
+    return False
+
+def time_complexities():
+    """
+    Return information on functions
+    time complexity
+    :return: string
+    """
+    return "Time complexity: O(logn)"
+
+
+def get_code():
+    """
+    easily retrieve the source code
+    of the function
+    :return: source code
+    """
+    return inspect.getsource(search)