From e9ba1e319633586638758ef27b64077cc8f179bb Mon Sep 17 00:00:00 2001
From: Shinjanee Gupta <shinjaneegupta@gmail.com>
Date: Mon, 16 Feb 2026 20:08:07 -0800
Subject: [PATCH] Missing number problem

---
 MissingNumber.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 MissingNumber.py

diff --git a/MissingNumber.py b/MissingNumber.py
new file mode 100644
index 00000000..aa686fb0
--- /dev/null
+++ b/MissingNumber.py
@@ -0,0 +1,20 @@
+# Time Complexity : O(log n)
+# Space Complexity : O(1)
+# Did this code successfully run on Leetcode : Yes
+# Any problem you faced while coding this : No
+# Approach : Use binary search to find the index where low and high indices cross each other. 
+
+class Solution:
+    def missingNumber(self, arr):
+        
+        low, high = 0, len(arr) - 1
+        
+        while low <= high:
+            mid = low + (high - low) // 2
+            
+            if arr[mid] <= (mid + 1):
+                low = mid + 1
+            else:
+                high = mid - 1
+        
+        return low + 1
\ No newline at end of file