【LeetCode 0169】【摩尔投票算法】主元素

169. Majority Element

Given an array nums of size n, return the majority element.

The majority element is the element that appears more than ⌊n / 2⌋ times. You may assume that the majority element always exists in the array.

Example 1:

**Input:** nums = [3,2,3] **Output:** 3 

Example 2:

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

Constraints:

• n == nums.length
• 1 <= n <= 5 * 10^4
• -10^9 <= nums[i] <= 10^9

Follow-up: Could you solve the problem in linear time and in O(1) space?

Idea

Boyer Moore Vote Algorithm  

JavaScript Solution

/**  * @param {number[]} nums  * @return {number}  */ var majorityElement = function(nums) {     [res,count] = [nums[0],0]     for(let n of nums){         if(count == 0){             [res,count] = [n,1]         }else{             if(res == n){                 count ++             }else{                 count --             }         }     }     return res; }; ```