LeetCode 169: Majority Element

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本文介绍了一种寻找数组中多数元素的方法，多数元素是指出现次数超过数组长度一半的元素。通过统计数组中每个位上1出现的次数，判断是否超过一半来确定多数元素。

Majority Element

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.

解题思路

class Solution {
public:
    int majorityElement(vector<int>& nums) {
        int n = nums.size();
        int bitNums[32] = {0};

        for (int i = 0; i < 32; ++i) {
            for (int j = 0; j < n; ++j) {
                if ((nums[j] >> i) & 1) {
                    bitNums[i]++;
                }
            }
        }

        int ans = 0;
        for (int i = 0; i < 32; ++i) {
            if (bitNums[i] > n / 2) {
                ans |= (1 << i);
            }
        }
        return ans;
    }
};