From 556c6e3637e04a9ca1e8b2b5687424d77e86b2f4 Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Wed, 10 Oct 2018 19:50:37 -0500
Subject: Binary Search iterative approach done!

Seems that recursive approach is better.---
 .../sources/binary_search.py                       | 35 ++++++++++++++--------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/AlgoDesignAndTechniqueEdxPython/sources/binary_search.py b/AlgoDesignAndTechniqueEdxPython/sources/binary_search.py
index 5f51289..21d3ad5 100644
--- a/AlgoDesignAndTechniqueEdxPython/sources/binary_search.py
+++ b/AlgoDesignAndTechniqueEdxPython/sources/binary_search.py
@@ -1,20 +1,32 @@
 # Uses python3
 import sys
 
-def binarySearchRecursive(a, low, high, key):
-    if high < low:
-        return -1
-    mid = (int) (low + (high - low) / 2)
-    if key == a[mid]:
-        return mid
-    elif key < a[mid]:
-        return binarySearchRecursive(a, low, mid - 1, key) 
-    else:
-        return binarySearchRecursive(a, mid + 1, high, key)
+# def binarySearchRecursive(a, low, high, key):
+#     if high < low:
+#         return -1
+#     mid = (int) (low + (high - low) / 2)
+#     if key == a[mid]:
+#         return mid
+#     elif key < a[mid]:
+#         return binarySearchRecursive(a, low, mid - 1, key) 
+#     else:
+#         return binarySearchRecursive(a, mid + 1, high, key)
+
+def binarySearchIterative(a, low, high, key):
+    while low <= high:
+        mid = (int) (low + (high - low)/2)
+        if key == a[mid]:
+            return mid;
+        elif key < a[mid]:
+            high = mid - 1
+        else:
+            low = mid + 1
+    return -1
 
 
 def binarySearch(a, key):
-    return binarySearchRecursive(a, 0, len(a) - 1, key)
+#     return binarySearchRecursive(a, 0, len(a) - 1, key)
+    return binarySearchIterative(a, 0, len(a) - 1, key)
 
 if __name__ == '__main__':
     input = sys.stdin.read()
@@ -23,5 +35,4 @@ if __name__ == '__main__':
     m = data[n + 1]
     a = data[1 : n + 1]
     for x in data[n + 2:]:
-        # replace with the call to binary_search when implemented
         print(binarySearch(a, x), end = ' ')
-- 
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