Merge pull request #58 from songhajang/ssong

feat(ssong): 7주차 과제

Author: songhajang

Songha/week7/b11724.java

@@ -0,0 +1,66 @@
+package algorithm.week7;
+
+import java.io.*;
+import java.util.*;
+
+public class b11724 {
+	static boolean visited[];
+	static ArrayList<Integer>[] A;
+	
+    public static void main(String[] args) throws IOException {	
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        
+        int n = Integer.parseInt(st.nextToken());
+        int m = Integer.parseInt(st.nextToken());
+        
+        visited = new boolean[n+1];
+        A = new ArrayList[n+1];
+        
+        
+        for(int i = 1; i < n+1; i++) {
+        	A[i] = new ArrayList<Integer>();
+        }
+        
+        for (int i = 0; i < m; i++) {
+        	// 입력값 받아오기
+			st = new StringTokenizer(br.readLine());
+			
+			int s = Integer.parseInt(st.nextToken());
+	        int e= Integer.parseInt(st.nextToken());
+	        
+	        A[s].add(e);
+	        A[e].add(s);
+	        
+		}
+        
+        
+        int count = 0;
+        for (int i = 1; i < n+1; i++) {
+			if(!visited[i]) {
+				count++;
+				
+				DFS(i);
+			}
+		}
+        
+        
+       System.out.println(count);
+        
+        
+    }
+
+	private static void DFS(int v) {
+		if(visited[v]) {
+			return ;
+		}
+		
+		// 재귀 함수
+		visited[v] = true;
+		for (int i : A[v]) {
+			if(!visited[i]) {
+				DFS(i);
+			}
+		}
+	}
+}

Songha/week7/b13023.java

@@ -0,0 +1,75 @@
+package algorithm.week7;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.StringTokenizer;
+
+public class b13023 {
+	static boolean isTrue;
+	static boolean visited [];
+	static ArrayList<Integer>[] A;
+	
+	static int n;
+	static int m;
+	
+	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()); // 친구 갯수
+		 m = Integer.parseInt(st.nextToken()); // 친구 관계 수
+	
+		
+		visited = new boolean[n+1];
+		A = new ArrayList[n+1];
+		
+		for (int i = 0; i < n; i++) {
+			A[i] = new ArrayList<Integer>();
+		}
+		
+		// 배열 만들기
+		for (int i = 0; i < m; i++) {
+			st = new StringTokenizer(br.readLine());
+			int s = Integer.parseInt(st.nextToken()); // 사람
+			int e = Integer.parseInt(st.nextToken()); // 관계
+			
+			A[s].add(e);
+			A[e].add(s);
+		}
+		
+		// backtraking	
+		for (int i = 0; i < n; i++) {
+			if(!isTrue) {
+				backtraking(i, 0);
+			}
+			
+		}
+		
+		
+		System.out.println(isTrue ? "1": "0");
+		
+	}
+
+	private static void backtraking(int v, int depth) {
+		
+		// 정답
+		if(depth == 4) {
+			isTrue = true;
+			return;
+		}
+
+		visited[v] = true;
+		for (int i : A[v]) {
+			if(!visited[i]) {
+				backtraking(i , depth+1);
+			}
+		}
+
+		visited[v] = false;
+		
+	}
+
+
+}

Songha/week7/b2023.java

@@ -0,0 +1,75 @@
+package algorithm.week7;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.StringTokenizer;
+
+public class b2023 {
+	static boolean isTrue;
+	static boolean visited [];
+	static ArrayList<Integer>[] A;
+	
+	static int n;
+	static int m;
+	
+	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()); // 친구 갯수
+		 m = Integer.parseInt(st.nextToken()); // 친구 관계 수
+	
+		
+		visited = new boolean[n+1];
+		A = new ArrayList[n+1];
+		
+		for (int i = 0; i < n; i++) {
+			A[i] = new ArrayList<Integer>();
+		}
+		
+		// 배열 만들기
+		for (int i = 0; i < m; i++) {
+			st = new StringTokenizer(br.readLine());
+			int s = Integer.parseInt(st.nextToken()); // 사람
+			int e = Integer.parseInt(st.nextToken()); // 관계
+			
+			A[s].add(e);
+			A[e].add(s);
+		}
+		
+		// backtraking	
+		for (int i = 0; i < n; i++) {
+			if(!isTrue) {
+				backtraking(i, 0);
+			}
+			
+		}
+		
+		
+		System.out.println(isTrue ? "1": "0");
+		
+	}
+
+	private static void backtraking(int v, int depth) {
+		
+		// 정답
+		if(depth == 4) {
+			isTrue = true;
+			return;
+		}
+
+		visited[v] = true;
+		for (int i : A[v]) {
+			if(!visited[i]) {
+				backtraking(i , depth+1);
+			}
+		}
+
+		visited[v] = false;
+		
+	}
+
+
+}