学校教的，学校的oj可以100，这里10

#include <bits/stdc++.h>
using namespace std;
int rright, lleft, middle, n, m, l, p, c[0x3f], d[0x3f];
bool k = 0;
int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> c[i];
    }
    for (int i = 1; i <= m; i++) {
        cin >> d[i];
    }
    sort(d + 1, d + m + 1);
    for (int i = 1; i <= n; i++) {
        rright = n;
        lleft = 1;
        k = 0;
        while (lleft <= rright) {
            middle = (lleft + rright) / 2;
            if (d[middle] >= c[i]) {
                rright = middle - 1;
            } else {
                lleft = middle + 1;
            }
        }
        if (d[lleft] == c[i]) {
            k = 1;
            // middle++;
        }
        if (k == 1) {
            cout << d[lleft] << " ";
        }
    }
}