leetcode 136) Single Number

LV. Easy 😎

https://leetcode.com/problems/single-number/

Single Number - LeetCode

 

문제

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

 

Example 1:

Input: nums = [2,2,1]
Output: 1

Example 2:

Input: nums = [4,1,2,1,2]
Output: 4

Example 3:

Input: nums = [1]
Output: 1

 

Constraints:

• 1 <= nums.length <= 3 * 104
• -3 * 104 <= nums[i] <= 3 * 104
• Each element in the array appears twice except for one element which appears only once.

 

문제 해결법

값이 같은 숫자가 2개의 쌍을 가지고 있으니, 정렬을 해서 2개씩 확인해줘서 값이 다를 때 홀수 값을 리턴해주면 해결 완료!

 

해결 코드

class Solution {
public:
	int singleNumber(vector<int>& nums) {
		sort(nums.begin(), nums.end());
		for (int i = 0; i < nums.size() - 1; i += 2) {
			if (nums[i] != nums[i + 1])
				return nums[i];
		}
		return *(nums.end() - 1);
	}
};