Merge pull request nirmalnishant645#14 from nirmalnishant645/problem1

Missing Number in the array

268-Missing-Number.py

@@ -0,0 +1,22 @@
+'''
+Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.
+
+Example 1:
+
+Input: [3,0,1]
+Output: 2
+Example 2:
+
+Input: [9,6,4,2,3,5,7,0,1]
+Output: 8
+Note:
+Your algorithm should run in linear runtime complexity. Could you implement it using only constant extra space complexity?
+'''
+class Solution:
+    def missingNumber(self, nums: List[int]) -> int:
+        res = 0
+        for i in range(len(nums) + 1):
+            res ^= i
+            if i < len(nums):
+                res ^= nums[i]
+        return res