Leetcode 169. Majority Element

最新推荐文章于 2025-03-31 22:10:03 发布

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最新推荐文章于 2025-03-31 22:10:03 发布

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本文链接：https://blog.youkuaiyun.com/Scarlett_leetcode/article/details/50708188

版权

本文介绍了一种专门的选举算法，用于在给定数组中找到出现次数超过一半的元素，即多数元素。通过Boyer-Moore多数投票算法实现，确保在数组中找到唯一且存在的多数元素。

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Problem

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.

Credits:
Special thanks to @ts for adding this problem and creating all test cases

Solution

有一个专门的选举算法

https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_majority_vote_algorithm

class Solution {
public:
    int majorityElement(vector<int>& nums) {
       if(nums.empty()) return -1;
       
       int rst = nums[0], count = 1;
       for( int i = 1; i < nums.size(); i++ ){
           if( nums[i] == rst) count++;
           else {
               count--;
               if(count == 0) {rst = nums[i]; count++;}
           }
       }
       return rst;
    }
};