테트로미노 / 골드 4 / 672ms

Author: SeoYeonLee12

src/N14500/N14500_seoyeon.java

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+package N14500;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.util.StringTokenizer;
+
+public class N14500_seoyeon {
+    // 지도 크기
+    static int N, M;
+    // 게임 배열
+    static int[][] game = new int[510][510];
+    // 테트로미노 합 가질 변수, 가장 큰 합을 저장할 변수
+    static int sum, maxSum;
+    // 방문 배열
+    static boolean[][] visited = new boolean[510][510];
+    // 방향 배열
+    static int[] dr = {-1, 1, 0, 0};
+    static int[] dc = {0, 0, -1, 1};
+
+    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());
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < M; j++) {
+                game[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+
+        for (int i = 0; i < N; i++) {
+            for (int j = 0; j < M; j++) {
+                // 방문 처리
+                visited[i][j] = true;
+                dfs(i, j, 1, game[i][j]);
+                visited[i][j] = false;
+                checkT(i, j);
+            }
+        }
+
+        bw.write(Integer.toString(maxSum));
+        bw.flush();
+        bw.close();
+        br.close();
+
+    }
+
+    // T 모양을 검사하는 함수
+    private static void checkT(int r, int c) {
+        //ㅜ
+        if (r >= 0 && r + 1 < N && c - 1 >= 0 && c + 1 < M) {
+            int sum = game[r][c] + game[r + 1][c - 1] + game[r + 1][c] + game[r + 1][c + 1];
+            if (maxSum < sum) {
+                maxSum = sum;
+            }
+        }
+        //ㅗ
+        if (r + 1 < N && c - 1 >= 0 && c + 1 < M) {
+            sum = game[r][c] + game[r + 1][c] + game[r][c - 1] + game[r][c + 1];
+            if (sum > maxSum) {
+                maxSum = sum;
+            }
+        }
+
+        // ㅓ
+        if (r - 1 >= 0 && r + 1 < N && c - 1 >= 0) {
+            sum = game[r][c] + game[r - 1][c] + game[r + 1][c] + game[r][c - 1];
+            if (sum > maxSum) {
+                maxSum = sum;
+            }
+        }
+
+        // ㅏ
+        if (r - 1 >= 0 && r + 1 < N && c + 1 < M) {
+            sum = game[r][c] + game[r - 1][c] + game[r + 1][c] + game[r][c + 1];
+            if (sum > maxSum) {
+                maxSum = sum;
+            }
+        }
+    }
+
+    private static void dfs(int r, int c, int depth, int currSum) {
+        // base condition
+        if (depth == 4) {
+            if (currSum > maxSum) {
+                maxSum = currSum;
+            }
+            return;
+        }
+
+        // 탐색
+        for (int i = 0; i < dr.length; i++) {
+            int nr = r + dr[i];
+            int nc = c + dc[i];
+
+            // 배열 범위 초과 확인, 방문 체크
+            if (nr < 0 || nr >= N || nc < 0 || nc >= M || visited[nr][nc]) {
+                continue;
+            }
+
+            visited[nr][nc] = true;
+            dfs(nr, nc, depth + 1, currSum + game[nr][nc]);
+            // 백트래킹
+            visited[nr][nc] = false;
+
+        }
+    }
+
+}