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  1. #include <iostream>
  2. #include <string>
  3. #include <stack>
  4. #include <fstream>
  5.  
  6. using namespace std;
  7.  
  8. bool prec(char cur)
  9. {
  10.         if( cur == '*' || cur == '/') return 1;
  11.         if( cur == '+' || cur == '-') return 0;
  12. }
  13.  
  14. void reverse(string &s, int st, int en)
  15. {
  16.         if( st <= en )
  17.         {
  18.                 char ch = s[st];
  19.                 s[st] = s[en];
  20.                 s[en] = ch;
  21.                 reverse(s, ++st, --en);
  22.         }
  23. }
  24.  
  25. void infix_to_postfix(string &s)
  26. {
  27.         stack<char> output;
  28.         stack<char> oper;
  29.         int len = s.size();
  30.  
  31.         for(int i = 0; i < len; ++i)
  32.         {
  33.                 if( isdigit(s[i]))
  34.                         output.push(s[i]);
  35.                 else
  36.                 {
  37.                         if( s[i] == '(' )
  38.                                 oper.push(s[i]);
  39.                         else if( s[i] == ')')
  40.                         {
  41.                                 while( !oper.empty() && oper.top() != '(')
  42.                                 {
  43.                                         output.push(oper.top());
  44.                                         oper.pop();
  45.                                 }
  46.                                 oper.pop();
  47.                         }
  48.                         else
  49.                         {
  50.                                 if( !oper.empty() && oper.top() != '(' && oper.top() != ')')
  51.                                 {
  52.                                         while( !oper.empty() && (prec(s[i]) < prec(oper.top())) )
  53.                                         {
  54.                                                 output.push(oper.top());
  55.                                                 oper.pop();
  56.                                         }
  57.                                         if( !oper.empty() && (prec(s[i]) == prec(oper.top())) )
  58.                                         {
  59.                                                 output.push(oper.top());
  60.                                                 oper.pop();
  61.                                         }
  62.  
  63.                                 }
  64.                                 oper.push(s[i]);
  65.                         }
  66.                 }
  67.         }
  68.         while(!oper.empty())
  69.         {
  70.                 output.push(oper.top());
  71.                 oper.pop();
  72.         }
  73.  
  74.         string so;
  75.         while(!output.empty())
  76.         {
  77.                 so += output.top();
  78.                 output.pop();
  79.         }
  80.  
  81.         reverse(so, 0, so.size()-1);
  82.         cout << so << endl;
  83. }
  84.  
  85. int main()
  86. {
  87.  
  88.  
  89.         int test;
  90.         cin >> test;
  91.         cin.ignore();
  92.         cin.ignore();
  93.         char ch;
  94.         string s, str;
  95.  
  96.         int k = 0;
  97.         while(k < test)
  98.         {
  99.                 while( getline(cin, str) )
  100.                 {
  101.                         if(str.size() == 0 )
  102.                                 break;
  103.                         s += str;
  104.                 }
  105.  
  106.                 k++;
  107.                 infix_to_postfix(s);
  108.  
  109.                 if( k != test)
  110.                         cout << endl;
  111.                 str.clear();
  112.                 s.clear();
  113.         }
  114.  
  115.         return 0;
  116. }
  117.  
Success #stdin #stdout 0s 2996KB
comments (?)
stdin
copy 
7

(
3
+
2
)
*
5

1
*
2
(
1
+
2
)
1
+
2

3
+
4
*
5
/
6

(
300
+
23
)
*
(
43
-
21
)
/
(
84
+
7
)

(
4
+
8
)
*
(
6
-
5
)
/
(
(
3
-
2
)
*
(
2
+
2
)
)

(
3
*
5
/
2
*
6
/
(
3
+
2
)
*
5
)
+
4

0
*
8
-
4
*
6
+
4
/
7
*
2
stdout
copy 
32+5*

1212+1*2+

345*6/+

30023+4321-*847+/

48+65-*32-22+*/

35*2/6*32+/5*4+

08*46*-47/2*+
https://ideone.com/yvuQZE
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
secret

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