【摩尔投票】169.多数元素

题目

法1：摩尔投票

相同题目：剑指：过半元素

Python

class Solution:
    def majorityElement(self, nums: List[int]) -> int:
        if len(nums) == 1:
            return nums[0]
        vote = 1
        res = nums[0]
        n = len(nums)
        for i in range(1, n):
            if nums[i] == res:
                vote += 1
            else:
                vote -= 1
                if vote == 0:
                    res = nums[i]
                    vote = 1
        
        return res

Java

class Solution {
    public int majorityElement(int[] nums) {
        if (nums.length == 1) {
            return nums[0];
        }
        int vote = 1, res = nums[0];
        for (int i = 1; i < nums.length; ++i) {
            if (nums[i] == res) {
                ++vote;
            } else {
                --vote;
                if (vote == 0) {
                    res = nums[i];
                    vote = 1;
                }
            }
        }
        return res;
    }
}

// 简化代码
class Solution {
    public int majorityElement(int[] nums) {
        int vote = 0, res = 0;
        for (int i = 0; i < nums.length; ++i) {
            res = vote == 0 ? nums[i] : res;
            vote += res == nums[i] ? 1 : -1;
        }
        return res;
    }
}