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swexpert_1224.java
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swexpert_1224.java
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package com.ssafy.algo;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;
public class swexpert_1224 {
static String getPostfix(String input) {
String result = "";
Stack<Character> stack = new Stack<>();
for (int i = 0; i < input.length(); i++) {
char ch = input.charAt(i);
if (ch >= '0' && ch <= '9') {
result += ch;
} else if (ch == ')') {
char temp;
while ((temp = stack.pop()) != '(') {
result += temp;
}
} else {
while (!stack.isEmpty() && ch != '('
&& getPriority(stack.peek()) >= getPriority(ch)) {
result += stack.pop();
}
stack.push(ch);
}
}
while (!stack.isEmpty()) {
result += stack.pop();
}
return result;
}
static int calPost(String postfix) { // 후위표기식을 계산하는 메서드
Stack<Integer> stack2 = new Stack<>();
for (int i = 0; i < postfix.length(); i++) {
char c = postfix.charAt(i);
if (c >= '0' && c <= '9') {
stack2.push(c - '0');
} else if (c == '+') {
int a = stack2.pop();
int b = stack2.pop();
stack2.push(a + b);
} else if (c == '*') {
int cc = stack2.pop();
int d = stack2.pop();
stack2.push(cc * d);
}
}
return stack2.pop();
}
static int getPriority(char c) { // 특정 연산자의 우선순위를 숫자로 리턴하는 메서드
if (c == '(') {
return 1;
} else if (c == '+') {
return 2;
} else if (c == '*') {
return 3;
} else {
return 0;
}
}
public static void main(String[] args) throws NumberFormatException, IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
for (int i = 1; i <= 10; i++) {
int len = Integer.parseInt(br.readLine().trim());
String str = br.readLine().trim();
String postfixStr = getPostfix(str);
System.out.printf("#%d %d\n", i, calPost(postfixStr));
}
}
}