A single element in an ordered array

An ordered array of integers only , Each of these elements will appear twice , Only one number will appear only once , Design an algorithm to find this number and return .

for example ：

Input ：[ 1,1,2,2,3,3,4,5,5 ]

Output ：4

Input ：[ 3,3,4,4,5,5,6 ]

Output ：6

Except that a number only appears once , Every other number will appear twice , Note that this ordered array must contain an odd number of numbers , And the subscript of a number that only appears once must be an even number . And the array is ordered , You can use binary search to get results .

int singleNonDuplicate(int* nums, int numsSize) {
    int left=0;
    int right=numsSize-1;
    while(low<high){
        int mid=left+(right-left)/2;// Two points search 
        mid-=mid&1;// Odd number &1 by 1, even numbers &1 by 0
        if(nums[mid]==nums[mid+1]){// If equal, it means 
            left+=2;// Traverse only numbers with even Subscripts 
        }
        else right=mid;
    }
    return nums[left];
}