Journal Archive

2022

/**
 * @param {number[]} nums
 * @return {number}
 */
var singleNumber = function(nums) {
    const occurance = new Set();
    for (const num of nums) {
        if (!occurance.has(num)) {
            occurance.add(num);
        } else {
            occurance.delete(num);
        }
    }
    return occurance.values().next().value;
};

Day 57: Solving one of LeetCode problems

136. Single Number Difficulty - Easy

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.