Merge pull request #1042 from AlgorithmWithGod/Ukj0ng

[20251004] BOJ / G1 / 전구를 켜라 / 한종욱

Author: ShinHeeEul

Ukj0ng/202510/04 BOJ G1 전구를 켜라.md

@@ -0,0 +1,97 @@
+```
+import java.io.*;
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Deque;
+import java.util.StringTokenizer;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static final int[] dx = {1, 1, -1, -1};
+    private static final int[] dy = {1, -1, 1, -1};
+    private static final char[] need = {'\\', '/', '/', '\\'};
+    private static int[][] dist;
+    private static char[][] map;
+    private static int N, M;
+
+    public static void main(String[] args) throws IOException {
+        init();
+
+        int answer = BFS();
+
+        if (answer == -1) {
+            bw.write("NO SOLUTION");
+        } else {
+            bw.write(answer + "");
+        }
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+
+        map = new char[N][M];
+        dist = new int[N+1][M+1];
+
+        for (int i = 0; i < N; i++) {
+            map[i] = br.readLine().toCharArray();
+        }
+
+        for (int i = 0; i <= N; i++) {
+            Arrays.fill(dist[i], Integer.MAX_VALUE);
+        }
+    }
+
+    private static int BFS() {
+        Deque<int[]> dq = new ArrayDeque<>();
+        dist[0][0] = 0;
+        dq.add(new int[]{0, 0, 0});
+
+        while (!dq.isEmpty()) {
+            int[] current = dq.poll();
+
+            if (dist[current[0]][current[1]] < current[2]) continue;
+
+            for (int i = 0; i < 4; i++) {
+                int nx = current[0] + dx[i];
+                int ny = current[1] + dy[i];
+
+                if (OOBPoint(nx, ny)) continue;
+
+                int gx = Math.min(current[0], nx);
+                int gy = Math.min(current[1], ny);
+
+                if (OOBRange(gx, gy)) continue;
+
+                int cost = (map[gx][gy] == need[i]) ? 0 : 1;
+                int newDist = dist[current[0]][current[1]] + cost;
+
+                if (newDist < dist[nx][ny]) {
+                    dist[nx][ny] = newDist;
+
+                    if (cost == 0) {
+                        dq.addFirst(new int[]{nx, ny, newDist});
+                    } else {
+                        dq.addLast(new int[]{nx, ny, newDist});
+                    }
+                }
+            }
+        }
+
+        return dist[N][M] == Integer.MAX_VALUE ? -1 : dist[N][M];
+    }
+
+    private static boolean OOBPoint(int nx, int ny) {
+        return nx < 0 || nx > N || ny < 0 || ny > M;
+    }
+
+    private static boolean OOBRange(int gx, int gy) {
+        return gx < 0 || gx >= N || gy < 0 || gy >= M;
+    }
+}
+```