[1227] 2573번 - 빙산

src/Problem2573.java

@@ -0,0 +1,126 @@
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.IOException;
+import java.util.StringTokenizer;
+import java.util.Queue;
+import java.util.LinkedList;
+
+public class Problem2573 {
+    static int[] DN = {1, -1, 0, 0};
+    static int[] DM = {0, 0, 1, -1};
+    static Queue<int[]> melt = new LinkedList<>();
+    static Queue<int[]> count = new LinkedList<>();
+
+    static int sum = 0;
+    static int time = 0;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        int n = Integer.parseInt(st.nextToken());
+        int m = Integer.parseInt(st.nextToken());
+
+        int[][] iceburg = new int[n][m];
+
+        for (int i = 0; i < n; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < m; j++) {
+                iceburg[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+
+        while(true) {
+            // 덩어리 개수 세기
+            int iceburgCount = countIceburg(iceburg, n, m);
+
+            if (iceburgCount > 1) {
+                break;
+            }
+
+            if (melt.isEmpty()) {
+                time = 0;
+                break;
+            }
+
+            // 멜팅 로직
+            meltIceburg(iceburg, n, m);
+            time++;
+
+
+        }
+        bw.write(String.valueOf(time));
+        bw.flush();
+        bw.close();
+    }
+
+    public static int countIceburg(int[][] iceburg, int n, int m) {
+        sum = 0;
+
+        boolean[][] visited = new boolean[n][m];
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                visited[i][j] = false;
+            }
+        }
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                if (iceburg[i][j] > 0 && !visited[i][j]) {
+                    sum++;
+                    visited[i][j] = true;
+
+                    count.add(new int[]{i, j});
+
+                    while (!count.isEmpty()) {
+                        int[] cur = count.poll();
+                        int x = cur[0];
+                        int y = cur[1];
+                        int meltCount = 0;
+
+                        for (int k = 0; k < 4; k++) {
+                            int nx = x + DN[k];
+                            int ny = y + DM[k];
+
+                            if (nx >= 0 && nx < n && ny >= 0 && ny < m) {
+                                if (iceburg[nx][ny] == 0) {
+                                    meltCount++;
+                                }
+                                if (iceburg[nx][ny] > 0 && !visited[nx][ny]) {
+                                    visited[nx][ny] = true;
+                                    count.add(new int[]{nx, ny});
+                                }
+                            }
+                        }
+                        melt.add(new int[]{x, y, meltCount, time});
+                    }
+                }
+            }
+        }
+
+        return sum;
+    }
+
+    public static void meltIceburg(int[][] iceburg, int n, int m) {
+        while (!melt.isEmpty()) {
+            int[] cur = melt.peek();
+            if (cur[3] == time) {
+                melt.poll();
+                int x = cur[0];
+                int y = cur[1];
+                int meltCount = cur[2];
+
+                iceburg[x][y] -= meltCount;
+                if (iceburg[x][y] < 0) {
+                    iceburg[x][y] = 0;
+                }
+            }
+            else {
+                break;
+            }
+        }
+    }
+}