CCF 201903-2 二十四点

逃离我推掉我的手 2023-07-17 06:40 11阅读 0赞

CCF 201903-2 二十四点

//
    // Created by asimov on 2020/3/20.
    //CCF
    //201903-2 二十四点
    //
    #ifndef CSP_24P_H
    #define CSP_24P_H
    #endif //CSP_24P_H
    
    #include <bits/stdc++.h>
    
    using namespace std;
    
    stack<int> numStack;//操作数栈
    stack<char> operationStack;//操作符栈
    string str;
    
    int p() {
        int n, front, back, i, j;
        cin >> n;
        getchar(); //读取换行符,易漏！！！
        for (i = 0; i < n; i++) {
            while (!numStack.empty()) numStack.pop();//清空栈
            while (!operationStack.empty()) operationStack.pop();
            cin >> str;//读取字符串
            //cout<<str.length()<<endl;
    
            for (j = 0; j < str.length(); j++) {
                if (str[j] >= '0' && str[j] <= '9')//若为数字，压入nd栈中
                {
                    numStack.push(str[j] - '0');
                } else if (str[j] == '+') //若为'+',压入op栈中
                {
                    operationStack.push('+');
                } else if (str[j] == '-')//转化为"+"计算(即将正数存储为负数,而op栈中就可以存放'+'了)
                {
                    numStack.push((str[j + 1] - '0') * (-1));
                    operationStack.push('+');
                    j++;
                } else if (str[j] == 'x')//先乘除法，与下一个未压入栈的数字计算，将计算结果压入数栈；
                {
                    front = numStack.top();
                    numStack.pop();
                    back = str[j + 1] - '0';
                    numStack.push(front * back);
                    j++;//已经使用了后一位操作数 因此跳过
                } else if (str[j] == '/') {
                    front = numStack.top();
                    numStack.pop();
                    back = str[j + 1] - '0';
                    numStack.push(front / back);
                    j++;
                }
            }
            while (!operationStack.empty())//此时只剩下'+'未计算了
            {
    //            取两个操作数
                front = numStack.top();
                numStack.pop();
                back = numStack.top();
                numStack.pop();
    
                operationStack.pop();
                numStack.push(front + back);
            }
            //  cout<<numStack.top()<<endl;
            if (numStack.top() == 24)//取出栈中数字，看是否=24
                cout << "Yes" << endl;
            else
                cout << "No" << endl;
        }
        return 0;
    }

/\*  
10  
9+3+4x3  
5+4x5x5  
7-9-9+8  
5x6/5x4  
3+5+7+9  
1x1+9-9  
1x9-5/9  
8/5+6x9  
6x7-3x6  
6x4+4/5  
\*/

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