https://www.acmicpc.net/problem/1260

DFS에는 크게 stack을 이용한 방법과 재귀함수를 이용한 방법이 있고,
BFS는 queue를 이용해서 풀이해야 한다.
DFS와 BFS의 정석을적인 방법을 이용해 풀이하면된다.
DFS는 재귀로 간단하게 해결하였다.

C++ 코드

#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;

vector<int> edge[1001];
bool check[1001];

void DFS(int n) {		//재귀함수로 해결
	if (check[n] == true) return;

	check[n] = true;
	cout << n << " ";
	for (auto i : edge[n]) DFS(i);

}

void BFS(int n) {			//큐를 이용
	queue<int> q;
	q.push(n);
	check[n] = true;

	while (q.empty() == false) {
		int f = q.front();
		cout << f << " ";
		q.pop();
		for (int i : edge[f]) {
			if (check[i] == false) {
				q.push(i); check[i] = true;
			}
		}
	}
}

int main() {
	
	int n = 0, m = 0, v = 0;
	cin >> n >> m >> v;

	int a, b;

	while (m--) {
		cin >> a >> b;
		edge[a].push_back(b);
		edge[b].push_back(a);
	}

	for (int i = 1; i <= n; i++) sort(edge[i].begin(), edge[i].end());
	DFS(v);
	for (int i = 1; i <= n; i++) check[i] = false;
	cout << "\n";
	BFS(v);
	
}

C# 코드

using System.Collections;
using System.Collections.Generic;
using static System.Console;
using System;

class Program
{
    static ArrayList[] edge = new ArrayList[1001];
    static bool[] check = new bool[1001];

    static void DFS(int n)
    {
        if (check[n] == true) return;

        check[n] = true;
        Write($"{n} ");
        foreach (int i in edge[n]) DFS(i);
    }

    static void BFS(int n)
    {
        Queue q = new Queue();
        q.Enqueue(n);
        check[n] = true;

        while (q.Count != 0)
        {
            int f = (int)q.Dequeue();
            Write($"{f} ");
            foreach (int i in edge[f])
            {
                if (check[i] == false)
                {
                    q.Enqueue(i);
                    check[i] = true;
                }
            }
        }
    }

    public static void Main(string[] args)
    {
        for (int i = 0; i < 1001; i++) edge[i] = new ArrayList();

        string[] s = ReadLine().Split(' ');
        int N = int.Parse(s[0]), M = int.Parse(s[1]), v = int.Parse(s[2]);

        while (M-- > 0)
        {
            s = ReadLine().Split(' ');
            int a = int.Parse(s[0]);
            int b = int.Parse(s[1]);
            edge[a].Add(b);
            edge[b].Add(a);
        }

        for (int i = 0; i <= N; i++) edge[i].Sort();
        DFS(v);
        for (int i = 0; i <= N; i++) check[i] = false;
        Write("\n");
        BFS(v);


    }
}

java 코드

import java.io.*;
import java.util.*;

public class Main {

    static ArrayList<Integer>[] edge = new ArrayList[1001];
    static boolean[] check = new boolean[1001];

    static void DFS(int n){
        if(check[n] == true) return;

        check[n] = true;
        System.out.print(n + " ");
        for(int i : edge[n]){
            if(check[i] == false) DFS(i);
        }
    }

    static void BFS(int n){
        Queue<Integer> q = new LinkedList<>();
        q.add(n);
        check[n] = true;

        while(q.isEmpty() == false){
            int f = q.peek();
            q.poll();
            System.out.print(f + " ");
            for(int i : edge[f]){
                if(check[i] == false) {
                    q.add(i); check[i] = true;
                }
            }
        }
    }

    public static void main(String[] args) {
        for(int i = 0; i< 1001; i++) edge[i] = new ArrayList();
        Scanner s = new Scanner(System.in);
        int N = s.nextInt(); int M = s.nextInt(); int v = s.nextInt();

        while(M-- > 0){
            int a = s.nextInt();
            int b = s.nextInt();
            edge[a].add(b);
            edge[b].add(a);
        }

        for(int i =0 ; i<= N; i++) Collections.sort(edge[i]);
        DFS(v);
        for(int i =0 ; i<= N; i++) check[i] = false;
        System.out.println();
        BFS(v);

    }
}

kotlin 코드

import java.util.*
import kotlin.math.*

var edge = Array<ArrayList<Int>>(1001) {ArrayList<Int>()}
var check = BooleanArray(1001, {false})

fun DFS(n: Int){
    if(check[n] == true) return

    print("${n} ")
    check[n] = true
    for(i in edge[n]) DFS(i)
}

fun BFS(n: Int){
    var q = LinkedList<Int>()
    q.add(n)
    check[n] = true

    while(q.isEmpty() == false){
        var f = q.peek()
        q.poll()
        print("${f} ")
        for(i in edge[f]){
            if(check[i] == false){
                q.add(i)
                check[i] = true
            }
        }
    }
}

fun main(args: Array<String>){
    val s = Scanner(System.`in`)
    val N = s.nextInt()
    var M = s.nextInt()
    val v = s.nextInt()

    while(M-- >0){
        val a = s.nextInt()
        val b = s.nextInt()
        edge[a].add(b)
        edge[b].add(a)
    }

    for(i in 0..N) edge[i].sort()
    DFS(v)
    for(i in 0..N) check[i] = false
    println()
    BFS(v)

}

python 코드

from collections import deque

edge = []
for i in range(1001): edge.append([])
check = [False for _ in range(1001)]

def DFS(n):
    if check[n] == True:  return

    print(n, end=' ')
    check[n] = True
    for i in edge[n]:
        DFS(i)

def BFS(n):
    q = deque()
    q.append(n)
    check[n] = True

    while len(q) > 0:
        f = q.popleft()
        print(f, end=' ')
        for i in edge[f]:
            if check[i] == False:
                q.append(i)
                check[i] = True

N,M,v = map(int, input().split())

for i in range(M):
    a,b = map(int, input().split())
    edge[a].append(b)
    edge[b].append(a)

for i in range(N+1): edge[i].sort()
DFS(v)
print()
for i in range(N+1): check[i] = False
BFS(v)