fix: incorrect range detection in find_missing_number (TheAlgorithms#10361)

* Fix incorrect range detection in find_missing_number

* Support consecutive decreasing numbers

Added support for consecutive decreasing numbers in the find_missing_number function.

* Support unordered numbers

Author: ManpreetXSingh

bit_manipulation/missing_number.py

@@ -11,11 +11,18 @@ def find_missing_number(nums: list[int]) -> int:
     Example:
         >>> find_missing_number([0, 1, 3, 4])
         2
+        >>> find_missing_number([1, 3, 4, 5, 6])
+        2
+        >>> find_missing_number([6, 5, 4, 2, 1])
+        3
+        >>> find_missing_number([6, 1, 5, 3, 4])
+        2
     """
-    n = len(nums)
-    missing_number = n
+    low = min(nums)
+    high = max(nums)
+    missing_number = high
 
-    for i in range(n):
-        missing_number ^= i ^ nums[i]
+    for i in range(low, high):
+        missing_number ^= i ^ nums[i - low]
 
     return missing_number