From 2b6717e350ca87f64cfdb5518ee5ac8d2eb12e65 Mon Sep 17 00:00:00 2001
From: hnu202326010302 <1677625723@qq.com>
Date: Sat, 27 Sep 2025 16:40:59 +0800
Subject: [PATCH] ADD file via upload

---
 src/Expressionjurge.java | 96 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 src/Expressionjurge.java

diff --git a/src/Expressionjurge.java b/src/Expressionjurge.java
new file mode 100644
index 0000000..dfae5f4
--- /dev/null
+++ b/src/Expressionjurge.java
@@ -0,0 +1,96 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
+import java.util.Map;
+import java.util.HashMap;
+
+public class Expressionjurge {
+
+  public boolean hasError(String expression) {
+    try {
+      String cleanExpr = expression.replaceAll("\\s+", "");
+      List<Object> rpn = infixToRPN(cleanExpr);
+      return evaluateRPN(rpn);
+    } catch (Exception e) {
+      return true; // 任何异常都视为有错误
+    }
+  }
+
+  private static List<Object> infixToRPN(String expression) {
+    List<Object> output = new ArrayList<>();
+    Stack<Character> operators = new Stack<>();
+    StringBuilder number = new StringBuilder();
+    Map<Character, Integer> precedence = Map.of('+', 1, '-', 1, '*', 2, '/', 2);
+    for (int i = 0; i < expression.length(); i++) {
+      char c = expression.charAt(i);
+      if (Character.isDigit(c) || c == '.') {
+        number.append(c);
+      } else {
+        if (number.length() > 0) {
+          output.add(Double.parseDouble(number.toString()));
+          number = new StringBuilder();
+        }
+        if (c == '(') {
+          operators.push(c);
+        } else if (c == ')') {
+          while (!operators.isEmpty() && operators.peek() != '(') {
+            output.add(operators.pop());
+          }
+          if (!operators.isEmpty()) operators.pop();
+        } else if (isOperator(c)) {
+          while (!operators.isEmpty() && operators.peek() != '(' &&
+                  precedence.getOrDefault(operators.peek(), 0) >= precedence.get(c)) {
+            output.add(operators.pop());
+          }
+          operators.push(c);
+        }
+      }
+    }
+    if (number.length() > 0) {
+      output.add(Double.parseDouble(number.toString()));
+    }
+    while (!operators.isEmpty()) {
+      output.add(operators.pop());
+    }
+    return output;
+  }
+
+  private static boolean evaluateRPN(List<Object> rpn) {
+    Stack<Double> stack = new Stack<>();
+
+    for (Object token : rpn) {
+      if (token instanceof Double) {
+        stack.push((Double) token);
+      } else {
+        char operator = (Character) token;
+        if (stack.size() < 2) return true; // 表达式错误
+
+        double b = stack.pop();
+        double a = stack.pop();
+        double result;
+
+        switch (operator) {
+          case '+': result = a + b; break;
+          case '-':
+            result = a - b;
+            if (result < 0) return true; // 发现负数
+            break;
+          case '*': result = a * b; break;
+          case '/':
+            if (b == 0) return true; // 发现除零
+            result = a / b;
+            if (result < 0) return true; // 发现负数
+            break;
+          default: return true; // 未知运算符
+        }
+        stack.push(result);
+      }
+    }
+
+    return stack.size() != 1; // 如果栈中不是恰好一个元素，说明表达式错误
+  }
+
+  private static boolean isOperator(char c) {
+    return c == '+' || c == '-' || c == '*' || c == '/';
+  }
+}
\ No newline at end of file