Easy
https://leetcode.com/problems/majority-element/description/
Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.
You may assume that the array is non-empty and the majority element always exist in the array.
Example 1:
Input: [3,2,3]
Output: 3
Example 2:
Input: [2,2,1,1,1,2,2]
Output: 2
/**
* @param {number[]} nums
* @return {number}
*/
var majorityElement = function(nums) {
// 解法二：投票法（假如没有题干的约束“majority 的出现次数大于2/N”，投票算法就失败了，就用解题一里的暴力解法吧）
let count = 1;
let majority = nums[0];
for(let i = 1; i < nums.length; i++) {
if(count == 0) {
majority = nums[i];
}
if (nums[i] === majority) {
count ++;
} else {
count --;
}
return majority;
}
// 解法一：暴力解法，map 存储每个数字以及出现的次数，最后遍历 map 找出最大数
const map = new Map()
for (let i = 0; i < nums.length; i += 1) {
const element = nums[i]
const count = map.get(element)
map.set(element, count !== undefined ? count + 1 : 1)
}
let [majoritKey, majoritCount] = [0, 0]
let = undefined
for (let [key, value] of map) {
if(value > majoritCount) {
[majoritKey, majoritCount] = [key, value]
}
}
return majoritKey
};