[LeetCode] 540. Single Element in a Sorted Array

轉自LeetCode

Given a sorted array consisting of only integers where every element appears twice except for one element which appears once. Find this single element that appears only once.

Example 1:

Input: [1,1,2,3,3,4,4,8,8]
Output: 2

Example 2:

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

Note: Your solution should run in O(log n) time and O(1) space.

<Solution>

想法如下

• 利用 XOR 的特性來解這題。因為每個數都會出現兩次，所以 XOR 過後，都會歸零，最後剩下的就是答案

code 如下

Java

	class Solution {
	public int singleNonDuplicate(int[] nums) {
	int ans = 0;
	for(int n : nums) {
	ans ^= n;
	}
	return ans;
	}
	}

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