[20250320] BOJ / G2 / 안티 팰린드롬 / 권혁준

Author: oncsr

khj20006/202503/20 BOJ G2 안티 팰린드롬.md

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+```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 = new StringTokenizer("");
+
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static String nextToken() throws Exception {
+		if(!st.hasMoreTokens()) nextLine();
+		return st.nextToken();
+	}
+	static int nextInt() throws Exception { return Integer.parseInt(nextToken()); }
+	static long nextLong() throws Exception { return Long.parseLong(nextToken()); }
+	static double nextDouble() throws Exception { return Double.parseDouble(nextToken()); }
+	static void bwEnd() throws Exception {bw.flush();bw.close();}
+	
+	// Additional field
+	
+	static int[] cnt;
+	static int N;
+	static String ans;
+	
+	public static void main(String[] args) throws Exception {
+		
+		ready();
+		solve();
+	
+		bwEnd();
+		
+	}
+	
+	static void ready() throws Exception{
+		
+		String s = br.readLine();
+		N = s.length();
+		cnt = new int[26];
+		for(char c : s.toCharArray()) cnt[c-'a']++;
+		
+	}
+	
+	static void solve() throws Exception{
+
+		for(int i=0;i<26;i++) if(cnt[i] > (N+1)/2) {
+			bw.write("-1");
+			return;
+		}
+		
+		ans = new String();
+		for(int i=0;i<26;i++) if(cnt[i] > 0) {
+			if(ans.length() > (N+1)/2 || ans.length() + cnt[i] <= (N+1)/2) {
+				while(cnt[i] > 0) {
+					ans += (char)('a'+i);
+					cnt[i]--;
+				}
+			}
+			else if(N%2 == 1 && ans.length() == N/2) {
+				while(cnt[i] > 0) {
+					ans += (char)('a'+i);
+					cnt[i]--;
+				}
+			}
+			else {
+				int need = 0;
+				while(ans.length() < (N+1)/2) {
+					ans += (char)('a'+i);
+					need++;
+				}
+				cnt[i] -= need;
+				if(N%2 == 1) need--;
+				
+				for(int j=i+1;j<26;j++) while(cnt[j] > 0 && need > 0) {
+					cnt[j]--;
+					ans += (char)('a'+j);
+					need--;
+				}
+				while(cnt[i] > 0) {
+					ans += (char)('a'+i);
+					cnt[i]--;
+				}
+				
+			}
+		}
+		bw.write(ans);
+
+	}
+	
+}
+
+```