7-53 两个有序序列的中位数 (25分)--vector

#include <iostream>
#include <vector>
using namespace std;

int main()
{
    int N;
    cin >> N;
    vector<int> s1, s2, s3;
    for (int i = 0; i < N; i++)
    {
        int in;
        cin >> in;
        s1.push_back(in);
    }
    for (int i = 0; i < N; i++)
    {
        int in;
        cin >> in;
        s2.push_back(in);
    }
    int p1 = 0;
    int p2 = 0;
    for (int i = 0; i < 2*N; i++)
    {
        if (p1 < N && p2 < N)
        {//注意下标边界问题，下标为N时不能使用s1[p1]或s2[p2]
            if (s1[p1] < s2[p2]) 
                s3.push_back(s1[p1++]);
            else 
                s3.push_back(s2[p2++]);
        }
        else
        {
            if(p1 < N)s3.push_back(s1[p1++]);
            else s3.push_back(s2[p2++]);
        }
    }
        cout << s3[(2*N-1)/2] <<endl;
    return 0;
}