[20251126] BOJ / G4 / 우유 도시 / 김민진

Author: zinnnn37

zinnnn37/202511/26 BOJ G4 우유 도시.md

@@ -0,0 +1,71 @@
+```java
+import java.io.*;
+import java.util.StringTokenizer;
+
+public class BJ_14722_우유_도시 {
+
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static StringTokenizer st;
+
+    private static int N;
+    private static int[][] milk;
+    private static Milk[][] dp;
+
+    private static class Milk {
+        int prev;
+        int cnt;
+
+        Milk(int prev, int cnt) {
+            this.prev = prev;
+            this.cnt = cnt;
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        init();
+        sol();
+    }
+
+    private static void init() throws IOException {
+        N = Integer.parseInt(br.readLine());
+
+        milk = new int[N + 1][N + 1];
+        dp = new Milk[N + 1][N + 1];
+
+        for (int i = 1; i <= N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 1; j <= N; j++) {
+                milk[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+
+        for (int i = 0; i <= N; i++) {
+            for (int j = 0; j <= N; j++) {
+                dp[i][j] = new Milk(0, 0);
+            }
+        }
+    }
+
+    private static void sol() throws IOException {
+        for (int i = 1; i <= N; i++) {
+            for (int j = 1; j <= N; j++) {
+                Milk fromUp = dp[i - 1][j];
+                Milk fromLeft = dp[i][j - 1];
+                Milk better = fromUp.cnt >= fromLeft.cnt ? fromUp : fromLeft;
+
+                if (milk[i][j] == better.prev) {
+                    dp[i][j] = new Milk((better.prev + 1) % 3, better.cnt + 1);
+                } else {
+                    dp[i][j] = new Milk(better.prev, better.cnt);
+                }
+            }
+        }
+
+        bw.write(dp[N][N].cnt + "");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+}
+```