C++ :

#include <bits/stdc++.h>
using namespace std;
int n,m;
int a[101000],b[101000];
bool binary_search(int x) {
	int l=1,r=n;
	while (l<=r) {
		int mid=(l+r)>>1;
		if (a[mid]==b[x])return 1;
		if (a[mid-1]<b[x]&&a[mid+1]>b[x])return 0;
		if (a[mid]>b[x])r=mid-1;
		else l=mid+1;
	}
	return 0;
}

int main() {
	cin>>n>>m;
	for(int i=1; i<=n; i++) cin>>a[i];
	for(int i=1; i<=m; i++) cin>>b[i];
	sort(a+1,a+1+n);
	sort(b+1,b+1+m);
	for(int i=1; i<=m; i++) if(binary_search(i)) cout<<b[i]<<" ";
}