[20251210] BOJ / G4 / 가장 긴 바이토닉 부분 수열 / 한종욱

Author: Ukj0ng

Ukj0ng/202512/10 BOJ G4 가장 긴 바이토닉 부분 수열.md

@@ -0,0 +1,61 @@
+```
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static int[] arr, dp, dp1, dp2;
+    private static int N, answer;
+
+    public static void main(String[] args) throws IOException {
+        init();
+        DP();
+
+        bw.write(answer + "\n");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        N = Integer.parseInt(br.readLine());
+
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        arr = new int[N];
+        dp = new int[N];
+        dp1 = new int[N];
+        dp2 = new int[N];
+
+        for (int i = 0; i < N; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+        }
+
+        Arrays.fill(dp1, 1);
+        Arrays.fill(dp2, 1);
+    }
+
+    private static void DP() {
+        for (int i = 1; i < N; i++) {
+            for (int j = 0; j < i; j++) {
+                if (arr[i] > arr[j]) {
+                    dp1[i] = Math.max(dp1[i], dp1[j]+1);
+                }
+            }
+        }
+
+        for (int i = N-2; i >= 0; i--) {
+            for (int j = N-1; j > i; j--) {
+                if (arr[i] > arr[j]) {
+                    dp2[i] = Math.max(dp2[i], dp2[j]+1);
+                }
+            }
+        }
+
+        for (int i = 0; i < N; i++) {
+            dp[i] = dp1[i] + dp2[i] - 1;
+            answer = Math.max(answer, dp[i]);
+        }
+    }
+}
+```