2 solutions

  • 1
    @ 2022-7-8 15:19:59

    浅写一个java的

    import java.util.ArrayList;
    import java.util.List;
    import java.util.Scanner;
    import java.util.Stack;
    
    public class Main {
        public static void main(String[] args) {
            Scanner in = new Scanner(System.in);
            String expression = in.nextLine();//注意表达式
            List<String> infixExpressionList = toInfixExpressionList(expression);
    //       System.out.println("中缀表达式对应的List=" + infixExpressionList);
            List<String> suffixExpreesionList = parseSuffExpressionList(infixExpressionList);
    //        System.out.println("后缀表达式对应的List" + suffixExpreesionList); //ArrayList [1,2,3,+,4,*,+,5,–]
            //        String suffixExpression = "4 5 * 8 - 60 + 8 2 / +"; // 76
    //        List<String> list = getListString(suffixExpression);
            int  res = calculate(suffixExpreesionList);
            System.out.println(res % 10000);
        }
        public static List<String> parseSuffExpressionList(List<String> ls){
            Stack<String> s1 = new Stack<>();
    //        Stack<String> s2 = new Stack<>();
            List<String> s2 = new ArrayList<>();
    
            for(String item : ls){
                if(item.matches("\\d+")){
                    s2.add(item);
                }else if(item.equals("(")){
                    s1.push(item);
                }else if(item.equals(")")){
                    while(!s1.peek().equals("(")){
                        s2.add(s1.pop());
                    }
                    s1.pop();
                }else {
                    while(s1.size() != 0 && Operation.getValue(s1.peek())>=Operation.getValue(item)){
                        s2.add(s1.pop());
                    }
                    s1.push(item);
                }
            }
            while(s1.size() != 0){
                s2.add(s1.pop());
            }
            return s2;
        }
    
        public static List<String> toInfixExpressionList(String s){
            List<String> list = new ArrayList<String>();
            int i = 0;
            String str;
            char c;
            do{
                if((c = s.charAt(i)) <48 || (c = s.charAt(i)) > 57){
                    list.add("" + c);//转换成字符串
                    i++;
                }else {
                    str = "";
                    while( i < s.length() && (c = s.charAt(i)) >= 48 && (c = s.charAt(i)) <= 57){
                        str += c;
                        i++;
                    }
                    list.add(str);
                }
            }while(i < s.length());
            return list;
        }
        public static List<String> getListString(String suffixExpression) {
            String split[] = suffixExpression.split(" ");
            List<String> list = new ArrayList<>();
            for (String element : split) {
                list.add(element);
            }
            return (list);
        }
    
        public static int calculate(List<String> ls) {
            Stack<String> stack = new Stack<String>();
            for (String element : ls) {
                if (element.matches("\\d+")) {
                    stack.push(element);
                } else {
                    int num2 = Integer.parseInt(stack.pop());
                    int num1 = Integer.parseInt(stack.pop());
                    int res = 0;
                    if (element.equals("+")) {
                        res = (num1 + num2) % 10000;
                    } else if (element.equals("-")) {
                        res = (num1 - num2) % 10000;
                    } else if (element.equals("*")) {
                        res = (num1 * num2) % 10000;
                    } else if (element.equals("/")) {
                        res = (num1 / num2) % 10000;
                    } else {
                        throw new RuntimeException("运算符有误");
                    }
                    stack.push("" + res);
                }
            }
            return Integer.parseInt(stack.pop());
        }
    }
    class Operation{
        private static int ADD = 1;
        private static int SUB = 1;
        private static int MUL = 2;
        private static int DIV = 2;
    
        public static int getValue(String operation){
            int result = 0;
            switch(operation){
                case "+":
                    result = ADD;
                    break;
                case "-":
                    result = SUB;
                    break;
                case "*":
                    result = MUL;
                    break;
                case "/":
                    result = DIV;
                    break;
                default:
                    break;
            }
            return result;
        }
    }
    

    Information

    ID
    290
    Time
    1000ms
    Memory
    128MiB
    Difficulty
    7
    Tags
    # Submissions
    82
    Accepted
    19
    Uploaded By