[20250311] BOJ / G2 / 후위 표기식 / 김수연

Author: suyeun84

suyeun84/202503/11 BOJ G2 후위 표기식.md

@@ -0,0 +1,51 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class boj1918 {
+	  static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static StringBuilder sb = new StringBuilder();
+    
+    public static void main(String[] args) throws Exception {
+    	String input = br.readLine();
+    	Stack<Character> stack = new Stack<>();
+    	for (int i = 0; i < input.length(); i++) {
+    		char c = input.charAt(i);
+    		switch(c) {
+	    		case '+':
+	    		case '-':
+	    		case '*':
+	    		case '/':
+	    			while (!stack.isEmpty() && priority(stack.peek()) >= priority(c)) {
+	    				sb.append(stack.pop());
+	    			}
+	    			stack.add(c);
+	    			break;
+	    		case '(':
+	    			stack.add(c);
+	    			break;
+	    		case ')':
+	    			while (!stack.isEmpty() && stack.peek() != '(') {
+	    				sb.append(stack.pop());
+	    			}
+	    			stack.pop();
+	    			break;
+	    		default:
+	    			sb.append(c);
+    		}
+    	}
+    	while (!stack.isEmpty()) {
+    		sb.append(stack.pop());
+    	}
+    	System.out.println(sb.toString());
+    }
+    
+    public static int priority(char op) {
+    	if (op == '(' || op ==')') return 0;
+    	else if (op == '+' || op == '-') return 1;
+    	else if (op == '*' || op == '/') return 2;
+    	return -1;
+    }
+}
+
+```