[20250730] BOJ / P4 / AK47 / 권혁준

Author: oncsr

khj20006/202507/30 BOJ P4 AK47.md

@@ -0,0 +1,107 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Main {
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+
+    public static void main(String[] args) throws Exception {
+
+        int T = Integer.parseInt(br.readLine());
+        while (T-- > 0) {
+
+            int N = Integer.parseInt(br.readLine());
+
+            if(N <= 47) naive(N);
+            else window(N);
+
+        }
+
+    }
+
+    static void naive(int N) throws Exception {
+        int a = -1, b = -1;
+        for(int i=1;i<=N;i++) {
+            if(shout(i,i)) {
+                if(a == -1) a = i;
+                else b = i;
+            }
+        }
+        bw.write("! " + a + " " + b + "\n");
+        bw.flush();
+    }
+
+    static void window(int N) throws Exception {
+        int s = 2, e = (N+2)/2 + 1;
+        int start = s-1, end = e-1;
+
+        // 맨 처음이 O인 경우
+        if(shout(s-1,e-1)) {
+            bw.write("! " + find(1,e-1) + " " + find(e,N) + "\n");
+            bw.flush();
+            return;
+        }
+
+        while(e <= N) {
+            if(shout(s,e)) {
+                if(s == 45 && e == 91) {
+                    if(shout(46,92)) {
+                        if(shout(46,46)) {
+                            bw.write("! 44 46\n");
+                            bw.flush();
+                        }
+                        else {
+                            bw.write("! 44 47\n");
+                            bw.flush();
+                        }
+                    }
+                    else {
+                        if(shout(91,91)) {
+                            bw.write("! 91 92\n");
+                            bw.flush();
+                        }
+                        else {
+                            bw.write("! 44 45\n");
+                            bw.flush();
+                        }
+                    }
+                }
+                else if(e < N && shout(e,e)) {
+                    bw.write("! " + e + " " + find(e+1,N) + "\n");
+                    bw.flush();
+                }
+                else {
+                    bw.write("! " + (s-1) + " " + find(s,end) + "\n");
+                    bw.flush();
+                }
+                return;
+            }
+            s++;
+            e++;
+        }
+        bw.write("! " + end + " " + (end-1) + "\n");
+        bw.flush();
+    }
+
+    static int find(int s, int e) throws Exception {
+        int m = (s+e)>>1;
+        while(s<e) {
+            if(shout(s,m)) e = m;
+            else {
+                s = m+1;
+                if(s == e) return s;
+            }
+            m = (s+e)>>1;
+        }
+        return m;
+    }
+
+    static boolean shout(int l, int r) throws Exception {
+        bw.write("AK " + l + " " + r + "\n");
+        bw.flush();
+        return br.readLine().charAt(0) == 'O';
+    }
+
+}
+```