Merge pull request #853 from AlgorithmWithGod/0224LJH

[20250909] BOJ / G3 / 레이저 통신 / 이종환

Author: ShinHeeEul

0224LJH/202509/09 BOJ 레이저 통신.md

@@ -0,0 +1,111 @@
+```java
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+public class Main {
+	static char[][] arr;
+	static int[][] dp;
+	static int width,height,goalY,goalX , curY,curX, curCnt,curDir,ans;
+	static boolean success = false;
+	
+	static Queue<Point> q = new LinkedList<>();
+	static int[] dy = {-1,0,1,0};
+	static int[] dx = {0,1,0,-1};
+	
+	static final char WALL = '*';
+	static final char GOAL = 'C';
+
+	
+	static class Point{
+		int y,x,dir;
+		
+		public Point(int y,int x,int dir) {
+			this.y = y;
+			this.x = x;
+			this.dir = dir;
+		}
+	}
+    
+    public static void main(String[] args) throws NumberFormatException, IOException {
+		init();
+		process();
+		print();
+    }
+    
+    public static void init() throws NumberFormatException, IOException {
+    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    	StringTokenizer st = new StringTokenizer(br.readLine());
+    	width = Integer.parseInt(st.nextToken());
+    	height = Integer.parseInt(st.nextToken());
+    	arr = new char[height][width];
+    	dp = new int[height][width];
+    	boolean first = true;
+    	
+    	for (int i = 0 ; i < height; i++) {
+    		String input = br.readLine();
+    		arr[i] = input.toCharArray();
+    		Arrays.fill(dp[i], Integer.MAX_VALUE/2);
+    		for (int j = 0; j < width; j++) {
+    			if (arr[i][j] == GOAL && first) {
+    				first = false;
+    				dp[i][j] = -1;
+    				for (int k = 0; k < 4; k++) q.add(new Point(i,j,k));
+    			} else if (arr[i][j] == GOAL) {
+    				goalY = i;
+    				goalX = j;
+    			} else if (arr[i][j] == WALL) {
+    				dp[i][j] = -1;
+    			}
+    		}
+    	}
+    	
+    }
+    
+    public static void process() { 	
+    	while(!q.isEmpty()) {
+    		int qLen = q.size();
+    		for (int i = 0; i < qLen; i++) {
+    			unitProcess();
+    		}
+    	}
+    }
+    
+    
+    public static void unitProcess() {
+		Point p = q.poll();
+		for (int j = 0; j < 4; j++) {
+			curY = p.y;
+			curX = p.x;
+			curDir = j;
+			curCnt = dp[curY][curX] +1 ;
+			if (curDir == p.dir) continue;
+			
+			while(true) {
+				curY += dy[curDir];
+				curX += dx[curDir];
+				if (curY == goalY && curX == goalX) {
+					ans = curCnt;
+				}
+				
+				if (curY >= height || curY < 0 || curX >= width || curX < 0 ) break;
+				if (arr[curY][curX] == WALL) break;
+				if (dp[curY][curX] <= curCnt) continue;
+				
+				dp[curY][curX] = curCnt;
+				q.add(new Point(curY,curX,j));
+				
+				
+				
+			}
+			
+		}
+    }
+
+    public static void print() {
+    	System.out.println(dp[goalY][goalX]);
+    }
+}
+```