Add solution for Missing Number

camp1/week3/leetcode/missing-number.py

@@ -0,0 +1,19 @@
+class Solution:
+    def missingNumber(self, nums: List[int]) -> int:
+        i=0
+        while i<len(nums):
+            correct=nums[i]
+            if correct==len(nums):
+                correct-=1
+                nums[correct],nums[i]=nums[i],nums[correct]
+                i+=1
+            elif correct!=i:
+                nums[correct],nums[i]=nums[i],nums[correct]
+            else:
+                i+=1
+        for i,num in enumerate(nums):
+            if i!=num:
+                return i
+        return i+1
+
+