BOJ #18258: 큐 2

Author: ISKU

BOJ/18258/Main.java

@@ -0,0 +1,55 @@
+/*
+ * Author: Minho Kim (ISKU)
+ * Date: January 9, 2010
+ * E-mail: minho.kim093@gmail.com
+ *
+ * https://github.com/ISKU/Algorithm
+ * https://www.acmicpc.net/problem/18258
+ */
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+	public static void main(String args[]) throws Exception {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		int N = Integer.parseInt(br.readLine());
+
+		LinkedList<String> q = new LinkedList<>();
+		while (N-- > 0) {
+			StringTokenizer st = new StringTokenizer(br.readLine());
+			String cmd = st.nextToken();
+
+			switch (cmd) {
+			case "push":
+				q.addLast(st.nextToken());
+				break;
+			case "pop":
+				bw.write(q.isEmpty() ? "-1" : q.removeFirst());
+				bw.write('\n');
+				break;
+			case "front":
+				bw.write(q.isEmpty() ? "-1" : q.getFirst());
+				bw.write('\n');
+				break;
+			case "back":
+				bw.write(q.isEmpty() ? "-1" : q.getLast());
+				bw.write('\n');
+				break;
+			case "size":
+				bw.write(String.valueOf(q.size()));
+				bw.write('\n');
+				break;
+			case "empty":
+				bw.write(q.isEmpty() ? '1' : '0');
+				bw.write('\n');
+				break;
+			default:
+				break;
+			}
+		}
+
+		bw.close();
+	}
+}