This post is completed by 2 users

Add to List 
139. Find Missing Numbers in Sequences  XOR Method
Input: Array, arrA[] with a missing number and Range
Output: missing number
Example:
int A[] = { 1, 2, 7, 6, 3, 4 }; int range = 7; Output: MIssing No is :5
In our earlier approach " Click Here " we have seen the method where we had calculated the Sum of numbers, but this approach might fail when the number goes beyond the integer range.
XOR method will better solution in that case.
Approach:  Time Complexity O(N), Space Complexity  O(1)
 Do the XOR if 1 to n say it A
 Do the XOR of the given array say it is B
 Do the XOR of A and B will give the missing no
Output:
MIssing No is :5