Algo for bisection search added

week_6/in_text/video_ques/bisection_search.py

@@ -0,0 +1,38 @@
+# using recussion
+
+# not effecient as a new copy of list is made on each recussion call
+def bisect_search1(L,e):
+    if L == []:
+        return False
+    elif len(L) == 1:
+        return L[0] == e
+    else:
+        half = len(L) // 2
+        if L[half] > e:
+            return bisect_search1(L[:half],e)
+        else:
+            return bisect_search1(L[half:],e)
+
+# the same copy of list  is reused
+def bisect_search2(L,e):
+    def bisect_search_helper(L, e, low, high):
+        if high == low:
+            return L[low] == e
+        mid = (low + high) // 2
+        if L[mid] == e:
+            return True
+        elif L[mid] > e:
+            if low == mid : #nothing left to search
+                return False
+            else:
+                return bisect_search_helper(L, e, low, mid - 1)
+        else:
+            return bisect_search_helper(L, e, mid + 1, high)
+    if len(L) == 0:
+        return False
+    else:
+        return bisect_search_helper(L, e, 0, len(L) - 1)
+if bisect_search2([1,2,3,4], 5) :
+    pass
+else:
+    print("yo")