合并排序的合并操作无法使用 c++ 向量

#include <iostream>
#include<vector>
std::vector<int> print(std::vector<int> answerVec){
    for(int i = 0; i < answerVec.size(); i++){
        std::cout<<answerVec.at(i)<<" ";
    }
    std::cout<<"n";
    return answerVec;
}
std::vector<int> Merge(std::vector<int> left, std::vector<int> right){
    int leftSize = left.size();
    int rightSize = right.size();
    std::vector<int> finalVector;
    int leftIterator = 0, rightIterator = 0;
    while(leftIterator < leftSize && rightIterator < rightSize){
        //std::cout<<"Left"<<left.at(leftIterator)<<"n";
        //std::cout<<"Right"<<right.at(rightIterator)<<"n";
        if((int)left.at(leftIterator) <= (int)right.at(leftIterator)){
            finalVector.push_back(left.at(leftIterator));
            leftIterator ++;
        }
        else{
            finalVector.push_back(right.at(rightIterator));
            rightIterator++;
        }
        //print(finalVector);
    }
    while(leftIterator < leftSize){
        finalVector.push_back(left.at(leftIterator));
        leftIterator ++;
        //print(finalVector);
    }
    while(rightIterator < rightSize){
        finalVector.push_back(right.at(rightIterator));
        rightIterator++;
        //print(finalVector);
    }
    return finalVector;
}
int main(){
    std::vector<int> vecL,vecR,vec;
    int n,input;
    std::cin>>n;
    for(int i = 0; i < n; i++){
        std::cin>>input;
        vecL.push_back(input);
    }
    for(int i = 0; i < n; i ++){
        std::cin>>input;
        vecR.push_back(input);
    }
    vec = Merge(vecL, vecR);
    for(int i = 0; i < vec.size(); i++){
        std::cout<<vec.at(i)<<" ";
    }
    return 0;
}

当我将两个排序向量作为参数传递时，上面的 Merge 函数无法正常工作。已经尝试了一段时间，但无法使其工作。评论了一些我用于调试的打印语句。任何帮助将不胜感激。

提前致谢