137.只出现一次的数字-ii.js

/*
 * @lc app=leetcode.cn id=137 lang=javascript
 *
 * [137] 只出现一次的数字 II
 */

// @lc code=start
/**
 * @param {number[]} nums
 * @return {number}
 */
var singleNumber = function (nums) {
  const map = new Map();
  for (let num of nums) {
    map.set(num, (map.get(num) || 0) + 1);
	}
	for (let [key,value] of map) {
		if (value === 1) {
		return key
	}
}
};
// @lc code=end

var singleNumber = function (nums) {
  let obj = {};
  for (let i = 0; i < nums.length; i++) {
    if (!obj[nums[i]]) {
      obj[nums[i]] = 1;
    } else {
      obj[nums[i]]++;
    }
  }
  for (let key in obj) {
    if (obj[key] == 1) {
      return key;
    }
  }
};