4.已知运算式判断合法性及求值

ゞ浴缸里的玫瑰 2022-06-02 09:58 142阅读 0赞

题目：给定后缀表达式，计算出该式的值。为简单起见，用于计算的数字均在0-9之间。

输入：

某个四则运算式的后缀表达式，其中除法"/"简化为整除。

输出：

该四则运算式的计算结果。若后缀表达式不合法，输出“ERROR!"；若计算过程中有除以0的情况，输出"DIV0!"

<table style="width:1615px; margin-bottom:20px; background-color:transparent"> 
 <thead> 
  <tr> 
   <th style="padding:4px; line-height:20px; vertical-align:bottom; border-top-width:0px"> &nbsp;</th> 
   <th style="padding:4px; line-height:20px; vertical-align:bottom; border-top-width:0px"> 测试输入<span><a href="http://online.bit.edu.cn/moodle/help.php?component=programming&amp;identifier=input&amp;lang=zh_cn" title="关于“测试输入”的帮助" style="color:rgb(67,142,185)" rel="nofollow"><img src="http://online.bit.edu.cn/moodle/theme/image.php/lambda/core/1510491239/help" alt="关于“测试输入”的帮助" style="vertical-align:text-bottom; border:0px; height:16px; padding-left:3px; width:16px"></a></span></th> 
   <th style="padding:4px; line-height:20px; vertical-align:bottom; border-top-width:0px"> 期待的输出<span><a href="http://online.bit.edu.cn/moodle/help.php?component=programming&amp;identifier=expectedoutput&amp;lang=zh_cn" title="关于“期待的输出”的帮助" style="color:rgb(67,142,185)" rel="nofollow"><img src="http://online.bit.edu.cn/moodle/theme/image.php/lambda/core/1510491239/help" alt="关于“期待的输出”的帮助" style="vertical-align:text-bottom; border:0px; height:16px; padding-left:3px; width:16px"></a></span></th> 
   <th style="padding:4px; line-height:20px; vertical-align:bottom; border-top-width:0px"> 时间限制<span><a href="http://online.bit.edu.cn/moodle/help.php?component=programming&amp;identifier=timelimit&amp;lang=zh_cn" title="关于“时间限制”的帮助" style="color:rgb(67,142,185)" rel="nofollow"><img src="http://online.bit.edu.cn/moodle/theme/image.php/lambda/core/1510491239/help" alt="关于“时间限制”的帮助" style="vertical-align:text-bottom; border:0px; height:16px; padding-left:3px; width:16px"></a></span></th> 
   <th style="padding:4px; line-height:20px; vertical-align:bottom; border-top-width:0px"> 内存限制<span><a href="http://online.bit.edu.cn/moodle/help.php?component=programming&amp;identifier=memlimit&amp;lang=zh_cn" title="关于“内存限制”的帮助" style="color:rgb(67,142,185)" rel="nofollow"><img src="http://online.bit.edu.cn/moodle/theme/image.php/lambda/core/1510491239/help" alt="关于“内存限制”的帮助" style="vertical-align:text-bottom; border:0px; height:16px; padding-left:3px; width:16px"></a></span></th> 
   <th style="padding:4px; line-height:20px; vertical-align:bottom; border-top-width:0px"> 额外进程<span><a href="http://online.bit.edu.cn/moodle/help.php?component=programming&amp;identifier=nproc&amp;lang=zh_cn" title="关于“{$a} 个额外进程”的帮助" style="color:rgb(67,142,185)" rel="nofollow"><img src="http://online.bit.edu.cn/moodle/theme/image.php/lambda/core/1510491239/help" alt="关于“{$a} 个额外进程”的帮助" style="vertical-align:text-bottom; border:0px; height:16px; padding-left:3px; width:16px"></a></span></th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="padding:4px; line-height:20px; vertical-align:middle; background-color:rgb(249,249,249)"> 测试用例 1</td> 
   <td style="padding:4px; line-height:20px; vertical-align:middle; background-color:rgb(249,249,249)"> <a href="http://online.bit.edu.cn/moodle/mod/programming/testcase/download_io.php?id=66667&amp;test=85761&amp;type=in&amp;download=0" style="color:rgb(67,142,185); font-size:9pt" rel="nofollow">以文本方式显示</a> 
    <div style="vertical-align:top; padding:0px 5px 0px 0px; width:10em; height:10em; overflow:auto"> 
     <ol style="padding-left:0px; margin-bottom:0px; margin-left:2.5em; overflow:visible"> 
      <li style="line-height:20px; font-family:Consolas,'Courier New',Courier,mono,serif; margin:0px; padding:0px; overflow:visible"> <span style="margin:0px; padding:0px; white-space:nowrap; background-color:rgb(211,211,211)">11+↵</span></li> 
     </ol> 
    </div> </td> 
   <td style="padding:4px; line-height:20px; vertical-align:middle; background-color:rgb(249,249,249)"> <a href="http://online.bit.edu.cn/moodle/mod/programming/testcase/download_io.php?id=66667&amp;test=85761&amp;type=out&amp;download=0" style="color:rgb(67,142,185); font-size:9pt" rel="nofollow">以文本方式显示</a> 
    <div style="vertical-align:top; padding:0px 5px 0px 0px; width:10em; height:10em; overflow:auto"> 
     <ol style="padding-left:0px; margin-bottom:0px; margin-left:2.5em; overflow:visible"> 
      <li style="line-height:20px; font-family:Consolas,'Courier New',Courier,mono,serif; margin:0px; padding:0px; overflow:visible"> <span style="margin:0px; padding:0px; white-space:nowrap; background-color:rgb(211,211,211)">2↵</span></li> 
     </ol> 
    </div> </td> 
   <td style="padding:4px; line-height:20px; vertical-align:middle; background-color:rgb(249,249,249)"> 1秒</td> 
   <td style="padding:4px; line-height:20px; vertical-align:middle; background-color:rgb(249,249,249)"> 64M</td> 
   <td style="padding:4px; line-height:20px; vertical-align:middle; background-color:rgb(249,249,249)"> 0</td> 
  </tr> 
 </tbody> 
</table>

#include<cstdio> 
    #include<string> 
    #include<map> 
    #include<stack> 
    #include<math.h> 
    #include<iostream> 
    using namespace std; 
     
    stack<char> Op; 
    stack<int>  Opnum; 
    string Instruction; 
    int GetproiIncoming(char c) 
    { 
     switch (c) 
     { 
      case('+') : return 3; 
      case('-') : return 3; 
      case('*') : return 5; 
      case('/') : return 5; 
      //case('%') : return 5; 
        //case('(') : return 10; 
       //case('^') : return 8; 
        } 
    } 
     
    int GetproInstack(char c) 
    { 
       switch (c) 
     { 
      case('+') : return 4; 
      case('-') : return 4; 
      case('*') : return 6; 
      case('/') : return 6; 
      //case('%') : return 6; 
        //case('(') : return 1; 
        //case('^') : return 7; 
        } 
    } 
    int Comput(char c, int a, int b) 
    { 
     switch (c) 
     { 
      case('+') : return a + b; 
      case('-') : return a - b; 
      case('*') : return a*b; 
        case('/') : return a / b; 
      //case('%') : return a%b; 
      //case('^') : return (int)pow(double(a), double(b)); 
       } 
    } 
     
    void getresult(string Instruction) 
    { 
      for (int i = 0; Instruction[i]; i++) 
       { 
          if (Instruction[i] >= '0'&&Instruction[i] <= '9') 
            { 
              int num = Instruction[i] - '0'; 
                Opnum.push(num); 
           } 
          else 
           { 
              if (Opnum.size() < 2) 
               { 
                  printf("ERROR!\n"); 
                    return; 
                } 
              else 
               { 
                  int a = Opnum.top(); Opnum.pop(); 
                  int b = Opnum.top(); Opnum.pop(); 
                  if (Instruction[i] == '/'&&a == 0) 
                 { 
                      printf("DIV0!\n"); 
                     return; 
                    } 
                  int num = Comput(Instruction[i], b, a); 
                    Opnum.push(num); 
               } 
          } 
      } 
      if (Opnum.size() > 1) 
       { 
          printf("ERROR!\n"); 
            return; 
        } 
      printf("%d\n",Opnum.top()); 
    } 
    int main() 
    { 
     getline(cin, Instruction); 
      getresult(Instruction); 
       return 0; 
    }