减治法——求两个序列的中位数

#include <iostream>
using namespace std;
int MidNum(int a[], int b[], int n);
int main()
{
    int a[100], b[100], i, n;
    cin >> n;
    for (i = 0; i < n; i++)
        cin >> a[i];
    for (i = 0; i < n; i++)
        cin >> b[i];
    cout << MidNum(a, b, n) << endl;
    ;
    return 0;
}

int MidNum(int a[], int b[], int n)
{
    int s1, e1, s2, e2, mid1, mid2;
    s1 = 0;
    s2 = 0;
    e1 = n - 1;
    e2 = n - 1;
    while (s1 < e1 && s2 < e2)
    {
        mid1 = (s1 + e1) / 2;
        mid2 = (s2 + e2) / 2;
        if (a[mid1] == b[mid2])
            return a[mid1];
        if (a[mid1] < b[mid2])
        {
            if ((s1 + e1) % 2 == 0)
                s1 = mid1;
            else
                s1 = mid1 + 1;
            e2 = mid2;
        }
        else
        {
            if ((s2 + e2) % 2 == 0)
                s2 = mid2;
            else
                s2 = mid2 + 1;
            e1 = mid1;
        }
    }
}