C :

#include<stdio.h>
#include<stdlib.h>
int a[1005],t[1005];
int h,p,n,m,x,f;
void p1(int k){
	if (f) { printf("%d",t[k]); f=0;}
		else printf(" %d",t[k]); 
	if (2*k<=n) p1(2*k);
	if (2*k+1<=n) p1(2*k+1);
}
void p2(int k){
	if (2*k<=n) p2(2*k);
	if (f) { printf("%d",t[k]); f=0;}
		else printf(" %d",t[k]); 
	if (2*k+1<=n) p2(2*k+1);
}
void p3(int k){
	if (2*k<=n) p3(2*k);
	if (2*k+1<=n) p3(2*k+1);
	if (f) { printf("%d",t[k]); f=0;}
		else printf(" %d",t[k]); 
}

int main(){
	int i;
	scanf("%d%d",&h,&p);
	n=(1<<h)-1;
	i=0;
	while (i<n) {
		scanf("%d",&x);
		if (a[x]==0) {
			i++;
			t[i]=x;
			a[x]=1;
		}
	}
	f=1;
	if (p==1) p1(1);
	if (p==2) p2(1);
	if (p==3) p3(1);
	return 0;
}

C++ :

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <algorithm>
#include <math.h>
#include <string.h>
#include <stack> 

using namespace std;

void find1(int i,vector<int> vec,int &count){
	if(count==1){
		count++;
		cout<<vec[i];
	}
	else{
		cout<<" "<<vec[i];
	}
	if(i*2<=vec.size()-1)
		find1(i*2,vec,count);
	if(i*2+1<=vec.size()-1)
		find1(i*2+1,vec,count);
	return ;
}

void find2(int i,vector<int> vec,int &count){
	
	
	if(i*2<=vec.size()-1)
		find2(i*2,vec,count);
	if(count==1){
		count++;
		cout<<vec[i];
	}
	else{
		cout<<" "<<vec[i];
	}
	if(i*2+1<=vec.size()-1)
		find2(i*2+1,vec,count);
	return ;
	
}

void find3(int i,vector<int> vec,int &count){
	if(i*2<=vec.size()-1)
		find3(i*2,vec,count);
	if(i*2+1<=vec.size()-1)
		find3(i*2+1,vec,count);
	if(count==1){
		count++;
		cout<<vec[i];
	}
	else{
		cout<<" "<<vec[i];
	}
	return ;
}

int main(){
	int h,p;
	string str;
	scanf("%d%d",&h,&p);
	vector<int> vec;
	int Num=pow(2,h)-1;
	int count=0;
	vec.insert(vec.end(),1001);
	while(1){
		int a;
		scanf("%d",&a);
		vector<int>::iterator isExit=find(vec.begin(),vec.end(),a);
		if(isExit==vec.end()){
			count++;
			vec.insert(vec.end(),a);
		}
		if(count==Num) break;
	}
	string strTemp;
	getline(cin,strTemp);
	if(p==1){
		int f=1;
		find1(1,vec,f);
	}
	else if(p==2){
		int f=1;
		find2(1,vec,f);
		
	}
	else if(p==3){
		int f=1;
		find3(1,vec,f);
	}
	cout<<endl;
	return 0;
}