Why does my C++ code consume more memory than Python for simple leetcode question?

Question is to check if array contains duplicate: https://leetcode.com/problems/contains-duplicate/description/

Its the same logic, but leetcode says c++ code took ~69mb and python ~29. Why is this so? Aren't C++ implementations supposed to be more efficient in general? Or maybe the leetcode estimates are not reliable?

C++ solution (

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        unordered_set<int> s;
        for(int x : nums){
            if(s.find(x)!=s.end())
                return true;
            s.insert(x);
        }
        return false;
    }
};

Python solution

class Solution(object):
    def containsDuplicate(self, nums):
        unq = set()
        for x in nums:
            if x in unq:
                return True
            unq.add(x)
        return False

Expected C++ to outperform Python in space consumed