LeetCode #414 Third Maximum Number

問題概要

入力値：nums
出力値：num
return the third distinct maximum number in this array
If the third maximum does not exist, return the maximum number
問題のリンク

入力例

nums: [1,2,3]
answer: 1

nums: [1,1,2]
answer: 2

解答例1

計算量：O(n)
Python

class Solution(object):
    def thirdMax(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        uniq_nums = list(set(nums))
        uniq_nums.sort()
        if len(uniq_nums) < 3:
            return uniq_nums[-1]
        else:
            return uniq_nums[-3]

Runtime: 31ms
Beats: 69.85%

C++

public:
    int thirdMax(vector<int>& nums) {
        set<int> numSet(nums.begin(), nums.end());
        auto it = numSet.rbegin();
        if (numSet.size() >= 3) {
            advance(it, 2);
        }
        return *it;
    }
};

Runtime: 12ms
Beats: 12.22%