From af346caff36a1d101685f33931e8b97e06bd3844 Mon Sep 17 00:00:00 2001
From: yess98 <52556037+yess98@users.noreply.github.com>
Date: Thu, 18 Nov 2021 12:48:15 +0900
Subject: [PATCH] =?UTF-8?q?[=EC=96=91=EC=9D=80=EC=84=9C]=20=EC=97=B0?=
 =?UTF-8?q?=EA=B5=AC=EC=86=8C3?=
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---
 ...\354\226\221\354\235\200\354\204\234.java" | 149 ++++++++++++++++++
 1 file changed, 149 insertions(+)
 create mode 100644 "solution/BOJ_17142_\354\227\260\352\265\254\354\206\214-3/\354\226\221\354\235\200\354\204\234.java"

diff --git "a/solution/BOJ_17142_\354\227\260\352\265\254\354\206\214-3/\354\226\221\354\235\200\354\204\234.java" "b/solution/BOJ_17142_\354\227\260\352\265\254\354\206\214-3/\354\226\221\354\235\200\354\204\234.java"
new file mode 100644
index 0000000..2334ffe
--- /dev/null
+++ "b/solution/BOJ_17142_\354\227\260\352\265\254\354\206\214-3/\354\226\221\354\235\200\354\204\234.java"
@@ -0,0 +1,149 @@
+```
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.StringTokenizer;
+
+public class Main{
+	static int n ; 
+	static int m ; 
+	static int [][] map;
+	static int [][] checkmap; 
+	static int wallcount = 0; 
+	static int viruscount = 0 ; 
+	static LinkedList <int []> virus_candidate = new LinkedList < int [] > (); 
+	static ArrayList < int [] > wall_position = new ArrayList < int [] >(); 
+	static boolean [] virus_candidate_check;
+	static boolean [][] check ; 
+	static int [] dx = {1,-1,0,0};
+	static int [] dy = {0,0,1,-1};
+	static int available; 
+	static Queue <int [] > queue = new ArrayDeque <int []>(); 
+	static int time; 
+	static int answer = Integer.MAX_VALUE ;
+	static boolean flag = false; 
+	static int blankcount = 0 ; 
+	
+	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()); 
+		map = new int [n][n]; 
+		for(int i = 0 ; i < n ; i ++) {
+			st = new StringTokenizer(br.readLine()); 
+			for(int j = 0 ; j < n ; j ++) {
+				map[i][j] = Integer.parseInt(st.nextToken()); 
+				//바이러스 설치 할 수 있는곳 저장시켜두기 
+				if (map[i][j] == 2) 
+					{
+						virus_candidate.add(new int [] {i,j});
+						viruscount ++; 
+					}
+				// 벽 개수 체크
+				if (map[i][j] == 1) 
+					{
+						wall_position.add(new int [] {i,j}); 
+						wallcount ++; 
+					}
+			}
+		}
+		virus_candidate_check = new boolean [virus_candidate.size()]; 
+		
+		// 빈칸의 갯수 = n * n - wallcount  - viruscount ; 
+		blankcount = n * n  - wallcount - viruscount; 
+		choose_position(0, 0);
+
+
+		if (flag == false) System.out.println(-1); 
+		else System.out.println(answer); 
+		
+	}
+	
+	
+	
+	static void put_virus () {
+		checkmap = new int[n][n]; 
+		queue = new ArrayDeque <int []>(); 
+		check = new boolean [n][n]; 
+		for(int i =  0 ; i < wall_position.size(); i ++) {
+			int [] temp = wall_position.get(i); 
+			checkmap[temp[0]][temp[1]] = -1 ;
+		}
+		for(int i = 0 ; i < virus_candidate_check.length; i ++) {
+			if (virus_candidate_check[i] == true ) {
+				int [] pos = virus_candidate.get(i); 
+				checkmap[pos[0]][pos[1]] = 0;
+				queue.add(new int[] {pos[0],pos[1],0});
+				check[pos[0]][pos[1]] = true; 
+			}
+			else {
+				int [] pos = virus_candidate.get(i); 
+				checkmap[pos[0]][pos[1]] = -2; 
+			}
+		}
+		
+		available = 0 ;
+		time = 0 ; 
+		infection(); 
+	
+	}
+	
+	static void choose_position(int cnt, int idx) {
+		if (cnt == m )
+		{
+			// 바이러스 넣을 부분  표시. 
+			put_virus (); 
+			return ; 
+		}
+		for(int i = idx ; i < virus_candidate.size(); i ++) {
+			if (virus_candidate_check[i] == false) {
+				virus_candidate_check[i] = true ;
+				choose_position(cnt + 1, i + 1); 
+				virus_candidate_check[i] = false ;
+			}
+		}
+	}
+	
+	static void infection() {
+
+		while (!queue.isEmpty()) {
+			int [] now = queue.poll();
+			
+	
+			for(int i = 0 ; i < dx.length; i ++) {
+				int nx = now[0] + dx[i]; 
+				int ny = now[1] + dy[i]; 
+				if (nx < 0 || ny < 0 || ny >= n || nx >= n) continue; 
+				if (check[nx][ny] == true ) continue; 
+				if (checkmap[nx][ny] == -1 ) continue;
+				if (checkmap [nx][ny] == -2 ) {
+					check[nx][ny] = true; 
+					queue.add(new int [] {nx,ny,now[2] + 1}); 
+					continue; 
+				}
+				queue.add(new int [] {nx,ny,now[2] + 1}); 
+				check[nx][ny] = true; 
+				available ++; 
+				time = now[2] + 1; 
+		
+			}
+			
+		}
+		
+		if (available == blankcount ) {
+			//가능
+			flag = true; 
+			if (answer > time) {
+				answer = time; 
+			}
+		}
+	}
+	
+}
+
+```