[20250214] BOJ / G2 / ㅋㅋ루ㅋㅋ / 권혁준

Author: oncsr

khj20006/202502/14 BOJ G2 ㅋㅋ루ㅋㅋ.md

@@ -0,0 +1,66 @@
+```java
+
+import java.util.*;
+import java.io.*;
+
+class Main {
+	
+	// IO field
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	static StringTokenizer st;
+
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static int nextInt() {return Integer.parseInt(st.nextToken());}
+	static long nextLong() {return Long.parseLong(st.nextToken());}
+	static void bwEnd() throws Exception {bw.flush();bw.close();}
+	
+	// Additional field
+    static String str;
+    static int[] left, right, R_cnt;
+    static int N;
+	
+	public static void main(String[] args) throws Exception {
+		
+		ready();
+		solve();
+	
+		bwEnd();
+		
+	}
+	
+	static void ready() throws Exception{
+		
+        str = new String("0"); // padding for prefix sum
+        str += br.readLine();
+        str += "0";
+        N = str.length()-2;
+
+        left = new int[N+2];
+        right = new int[N+2];
+        R_cnt = new int[N+2];
+
+	}
+	
+	static void solve() throws Exception{
+
+        for(int i=1;i<=N;i++) left[i] += left[i-1] + (str.charAt(i) == 'K' ? 1 : 0);
+        for(int i=N;i>=1;i--) right[i] += right[i+1] + (str.charAt(i) == 'K' ? 1 : 0);
+        for(int i=1;i<=N;i++) R_cnt[i] += R_cnt[i-1] + (str.charAt(i) == 'R' ? 1 : 0);
+        
+        int ans = 0;
+        int s = 0, e = N+1, K_cnt = 0;
+        while(s<e){
+            if(R_cnt[e-1] - R_cnt[s] == 0) break;
+            ans = Math.max(ans, R_cnt[e-1] - R_cnt[s] + K_cnt*2);
+            K_cnt++;
+            while(s<=N && left[s] < K_cnt) s++;
+            while(e>=1 && right[e] < K_cnt) e--;
+        }
+        bw.write(ans+"\n");
+		
+	}
+	
+}
+
+```