queue 직접구현, BFS

#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <stack>
#include <vector>
#include <math.h>
using namespace std;
int Q[100], front=-1, back=-1, ch[10];
vector<int> map[10];
int main() {
	//freopen("input.txt.txt","rt",stdin);
	int i, a, b, x;
	for(i=1; i<=6; i++){
		scanf("%d %d",&a, &b);
		map[a].push_back(b);
		map[b].push_back(a);
	}
	Q[++back]=1;
	ch[1]=1;
	
	while(front<back){
		x=Q[++front];
		printf("%d ",x);
		for(i=0; i<map[x].size(); i++){
			if(ch[map[x][i]]==0){
				ch[map[x][i]]=1;
				Q[++back] = map[x][i];
				
			}
		}
		
		
	}
	
	
}