[20251204] BOJ / G3 / 마법사 상어와 토네이도 / 이준희

Author: JHLEE325

JHLEE325/202512/04 BOJ G3 마법사 상어와 토네이도.md

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+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static int N;
+    static int[][] A;
+    static int answer;
+
+    static int[] dx = {0, 1, 0, -1};
+    static int[] dy = {-1, 0, 1, 0};
+
+    static int[][] dsx = {
+            { -1,  1, -2, -1,  1,  2, -1,  1,  0 },
+            { -1, -1,  0,  0,  0,  0,  1,  1,  2 },
+            {  1, -1,  2,  1, -1, -2,  1, -1,  0 },
+            {  1,  1,  0,  0,  0,  0, -1, -1, -2 }
+    };
+
+    static int[][] dsy = {
+            {  1,  1,  0,  0,  0,  0, -1, -1, -2 },
+            { -1,  1, -2, -1,  1,  2, -1,  1,  0 },
+            { -1, -1,  0,  0,  0,  0,  1,  1,  2 },
+            {  1, -1,  2,  1, -1, -2,  1, -1,  0 }
+    };
+
+    static int[] ratio = {1, 1, 2, 7, 7, 2, 10, 10, 5};
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+        N = Integer.parseInt(br.readLine());
+        A = new int[N][N];
+
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < N; j++) {
+                A[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+
+        simulate();
+        System.out.println(answer);
+    }
+
+    static void simulate() {
+        int x = N/2;
+        int y = N/2;
+
+        int len = 1;
+        int dir = 0;
+
+        while (true) {
+            for (int i = 0; i < 2; i++) {
+                for (int step = 0; step < len; step++) {
+
+                    x += dx[dir];
+                    y += dy[dir];
+
+                    spread(x, y, dir);
+
+                    if (x == 0 && y == 0) return;
+                }
+                dir = (dir + 1) % 4;
+            }
+            len++;
+        }
+    }
+
+    static void spread(int x, int y, int dir) {
+        int sand = A[x][y];
+        if (sand == 0) {
+            return;
+        }
+        A[x][y] = 0;
+
+        int used = 0;
+
+        for (int i = 0; i < 9; i++) {
+            int nx = x + dsx[dir][i];
+            int ny = y + dsy[dir][i];
+
+            int amount = (sand * ratio[i]) / 100;
+            used += amount;
+
+            if (nx < 0 || ny < 0 || nx >= N || ny >= N) {
+                answer += amount;
+            } else {
+                A[nx][ny] += amount;
+            }
+        }
+
+        int ax = x + dx[dir];
+        int ay = y + dy[dir];
+        int remain = sand - used;
+
+        if (ax < 0 || ay < 0 || ax >= N || ay >= N) {
+            answer += remain;
+        } else {
+            A[ax][ay] += remain;
+        }
+    }
+}
+```