BOJ #1918: 후위 표기식

Author: ISKU

BOJ/1918/1918.java

@@ -0,0 +1,54 @@
+/*
+ * Author: Minho Kim (ISKU)
+ * Date: November 13, 2019
+ * E-mail: minho.kim093@gmail.com
+ *
+ * https://github.com/ISKU/Algorithm
+ * https://www.acmicpc.net/problem/1918
+ */
+
+import java.util.*;
+import java.io.*;
+
+public class Main {
+	public static void main(String[] args) throws Exception {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		char[] line = br.readLine().toCharArray();
+
+		Stack<Character> stack = new Stack<>();
+		for (char c : line) {
+			if (c == '(') {
+				stack.push(c);
+			} else if (c == ')') {
+				while (!stack.isEmpty() && stack.peek() != '(')
+					System.out.print(stack.pop());
+				stack.pop();
+			} else if (c == '*' || c == '/') {
+				while (!stack.isEmpty() && getPriority(stack.peek()) >= 3)
+					System.out.print(stack.pop());
+				stack.push(c);
+			} else if (c == '+' || c == '-') {
+				while (!stack.isEmpty() && getPriority(stack.peek()) >= 2)
+					System.out.print(stack.pop());
+				stack.push(c);
+			} else {
+				System.out.print(c);
+			}
+		}
+		while (!stack.isEmpty())
+			System.out.print(stack.pop());
+	}
+
+	private static int getPriority(char c) {
+		switch (c) {
+		case '*':
+		case '/':
+			return 3;
+		case '+':
+		case '-':
+			return 2;
+		default:
+			return 1;
+		}
+	}
+}