#include <bits/stdc++.h>
using namespace std;
int a[100011];
const int K=18;
void send_message(vector<bool> M,vector<bool> C)
{
	// printf("send_message():\n");
	// printf("M:");for(bool x:M)printf("%d",x);putchar(10);
	// printf("C:");for(bool x:C)printf("%d",x);putchar(10);
	mt19937 rnd(801);
	vector<int> vs;
	vs.clear();
	for(int i=0;i<K;++i)vs.push_back(rnd()&(1<<16)-1);
	// printf("vs:");for(int x:vs)printf("%d ",x);putchar(10);
	for(int i=0;i<K;++i)
	{
		int pt=0;
		vector<bool> msg(C.size(),0);
		for(int j=0;j<C.size();++j)if(!C[j])msg[j]=vs[i]>>(pt++)&1;
		send_packet(msg);
	}
	M.push_back(1);
	int S=M.size(),pt=0;
	for(int i=0;i<(M.size()+15)/16;++i)
	{
		int pt=0;
		vector<bool> msg(C.size(),0);
		for(int j=0;j<C.size();++j)if(!C[j])
		{
			if(pt<M.size())msg[j]=M[pt++];
		}
		send_packet(msg);
	}
}
vector<bool> receive_message(vector<vector<bool>> R)
{
	mt19937 rnd(801);
	int a[16]={};
	for(int i=0;i<K;++i)
	{
		int X=rnd()&(1<<16)-1;
		for(int _=0;_<16;++_)if(X>>_&1)a[_]|=1<<i;
	}
	int b[31]={};
	for(int i=0;i<31;++i)
	{
		for(int _=0;_<K;++_)b[i]=b[i]|R[_][i]<<_;
	}
	vector<bool> C(31,0);
	int pt=0;
	for(int i=0;i<C.size();++i)
	{
		if(pt<16&&a[pt]==b[i])C[i]=1,++pt;
	}
	vector<bool> M;
	for(int i=K;i<R.size();++i)
	{
		for(int _=0;_<R[i].size();++_)if(C[_])M.push_back(R[i][_]);
	}
	while(!M.back())M.pop_back();
	M.pop_back();
	return M;
}

answer.code: In function ‘void send_message(std::vector<bool>, std::vector<bool>)’:
answer.code:20:17: error: ‘send_packet’ was not declared in this scope
   20 |                 send_packet(msg);
      |                 ^~~~~~~~~~~
answer.code:32:17: error: ‘send_packet’ was not declared in this scope
   32 |                 send_packet(msg);
      |                 ^~~~~~~~~~~