leetcode-540. A single element in an ordered array

540. A single element in an ordered array

Give you an ordered array of integers only , Each of these elements will appear twice , Only one number will appear once .

Please find and return the number that only appears once .

The solution you design must meet O(log n) Time complexity and O(1) Spatial complexity .

Example 1:

Input : nums = [1,1,2,3,3,4,4,8,8]
Output : 2
Example 2:

Input : nums = [3,3,7,7,10,11,11]
Output : 10

Tips :

1 <= nums.length <= 105
0 <= nums[i] <= 105

class Solution {
    
    public int singleNonDuplicate(int[] nums) {
    
      int min=0,max=nums.length-1;
      while(min<max){
    
          int mid=(min+max)/2;        // Or written （max-min）/2+min
          if(nums[mid]==nums[mid^1]){
       //  Be careful ： Here is bitwise XOR 
              min=mid+1;
          }
          else{
    
              max=mid;
          }
      }
      return nums[min];
    }
}