Leetcode題解 Python & C#：五月挑戰DAY6 Majority Element

給一個大小為 n 的陣列，找出出現次數超過 n/2 的元素。(可以預期這個元素一定存在)

這個是計數題，數一遍 n 並且統計出現次數，就能找到 majority element。

 Python

class Solution:
    def majorityElement(self, nums: List[int]) -> int:
        import collections
        counter =  collections.Counter(nums)
        n = len(nums)
        for key in counter:
            if counter[key] >= n/2:
                return key

C#

public class Solution {
    public int MajorityElement(int[] nums) {
        var counter = new Dictionary();
        int halfN = nums.Length/2 + (nums.Length%2==1 ? 1: 0);
        foreach(var num in nums)
        {
            counter[num] = 1 + (counter.ContainsKey(num) ? counter[num]: 0);
            if(counter[num] >= halfN)
            {
                return num;
            }
        }    
        return 0;
    }
}