[20250203] BAJ / G1 / 로봇 청소기 / 신희을

ShinHeeEul/202502/03 BOJ G1 로봇 청소기.md

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+```java
+    import java.io.*;
+    import java.util.*;
+
+    class Solution {
+        static char[][] map;
+        static int[][] dustDis;
+        static Node[] dusts;
+        static Map<Integer, Integer> dustIndex;
+        static int N = 1;
+        static int M = 1;
+        static boolean[][] visited;
+        static int count;
+        static BufferedReader br;
+        static StringTokenizer st;
+
+        public static void main(String args[]) throws Exception {
+            br = new BufferedReader(new InputStreamReader(System.in));
+            StringBuilder sb = new StringBuilder();
+
+            while (true) {
+                M = read();
+                N = read();
+                if (M == 0 && N == 0) break;
+
+                dusts = new Node[11];
+                count = 1;
+                dustIndex = new HashMap<>();
+                map = new char[N][M];
+
+                for (int i = 0; i < N; i++) {
+                    for (int j = 0; j < M; j++) {
+                        map[i][j] = (char) System.in.read();
+                        if (map[i][j] == '*') {
+                            dustIndex.put(i * 20 + j, count);
+                            dusts[count] = new Node(i, j);
+                            count++;
+                        }
+                        if (map[i][j] == 'o') {
+                            dusts[0] = new Node(i, j);
+                        }
+                    }
+                    System.in.read();
+                }
+
+                dustDis = new int[count + 1][count + 1];
+                for (int i = 0; i < count; i++) {
+                    bfs(dusts[i].i, dusts[i].j, i);
+                }
+
+                int ans = bitMasking();
+                sb.append(ans == 0 || ans == (Integer.MAX_VALUE >> 1) ? -1 : ans).append("\n");
+            }
+
+            System.out.print(sb);
+        }
+
+        public static int bitMasking() {
+            count--;
+            int[][] dustDP = new int[1 << count][count + 1];
+            for (int i = 0; i < (1 << count); i++)
+                Arrays.fill(dustDP[i], Integer.MAX_VALUE >> 1);
+
+            for (int i = 0; i < count; i++) dustDP[1 << i][i + 1] = dustDis[0][i + 1];
+
+            for (int i = 0; i < (1 << count); i++) {
+                for (int k = 1; k <= count; k++) {
+                    for (int j = 0; j < count; j++) {
+                        int a = 1 << j;
+                        int ba = a | i;
+                        if (ba == i || ba >= dustDP.length || dustDis[k][j + 1] == 0) continue;
+                        dustDP[ba][j + 1] = Math.min(dustDP[ba][j + 1], dustDP[i][k] + dustDis[k][j + 1]);
+                    }
+                }
+            }
+
+            int min = Integer.MAX_VALUE;
+            for (int i = 0; i <= count; i++) {
+                min = Math.min(dustDP[(1 << count) - 1][i], min);
+            }
+            return min;
+        }
+
+        public static void bfs(int si, int sj, int index) {
+            visited = new boolean[N][M];
+            int[] di = {1, -1, 0, 0};
+            int[] dj = {0, 0, 1, -1};
+
+            Queue<Dust> queue = new LinkedList<>();
+            queue.add(new Dust(si, sj, 0));
+            visited[si][sj] = true;
+
+            while (!queue.isEmpty()) {
+                Dust dust = queue.poll();
+                int i = dust.i;
+                int j = dust.j;
+                int count = dust.count;
+
+                int d = dustIndex.getOrDefault(i * 20 + j, -1);
+                if (d != -1) {
+                    dustDis[index][d] = count;
+                }
+
+                for (int k = 0; k < 4; k++) {
+                    int ii = i + di[k];
+                    int jj = j + dj[k];
+
+                    if (!check(ii, jj)) continue;
+                    visited[ii][jj] = true;
+                    queue.add(new Dust(ii, jj, count + 1));
+                }
+            }
+        }
+
+        public static boolean check(int i, int j) {
+            if (i < 0 || i >= N || j < 0 || j >= M) return false;
+            if (map[i][j] == 'x') return false;
+            return !visited[i][j];
+        }
+
+        public static class Node {
+            int i, j;
+            public Node(int i, int j) {
+                this.i = i;
+                this.j = j;
+            }
+        }
+
+        public static class Dust {
+            int i, j, count;
+            public Dust(int i, int j, int count) {
+                this.i = i;
+                this.j = j;
+                this.count = count;
+            }
+        }
+
+        private static int read() throws Exception {
+            int d, o;
+            boolean negative = false;
+            d = System.in.read();
+            if (d == '-') {
+                negative = true;
+                d = System.in.read();
+            }
+
+            o = d & 15;
+            while ((d = System.in.read()) > 32)
+                o = (o << 3) + (o << 1) + (d & 15);
+
+            return negative? -o:o;
+        }
+    }
+
+```