feat(Hansol): add /Baekjoon-13023.java

Hansol/august/Boj13023.java

@@ -0,0 +1,62 @@
+package fisa_cote.august;
+
+import java.io.*;
+import java.util.*;
+
+public class Boj13023 {
+
+	static int N, M, isEixst;
+	static List<Integer>[] list;
+	static boolean[] visited;
+	public static void main(String[] args) throws IOException{
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+
+		list = new ArrayList[N];
+		visited = new boolean[N];
+
+		for(int i = 0; i < N; i++) {
+			list[i] = new ArrayList<>();
+		}
+
+		for(int i = 0; i < M; i++) {
+			st = new StringTokenizer(br.readLine());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			list[a].add(b);
+			list[b].add(a);
+		}
+
+		isEixst = 0;
+
+		for(int i = 0; i < N; i++) {
+			visited[i] = true;
+			DFS(i,0);
+			visited[i] = false;
+		}
+
+		System.out.println(isEixst);
+
+	}
+
+
+	private static void DFS(int num, int count) {
+		if(isEixst == 1) return;
+
+		if(count == 4) {
+			isEixst = 1;
+			return;
+		}else {
+			for(int i : list[num]) {
+				if(!visited[i]) {
+					visited[i] = true;
+					DFS(i, count+1);
+					visited[i] = false;
+				}
+			}
+		}
+	}
+}