구조---이산수학, 중언식

Tautology
Time Limit: 1000MS
 
Memory Limit: 65536K
Total Submissions: 9053
 
Accepted: 3463
Description
WFF 'N PROOF is a logic game played with dice. Each die has six faces representing some subset of the possible symbols K, A, N, C, E, p, q, r, s, t. A Well-formed formula (WFF) is any string of these symbols obeying the following rules:

p, q, r, s, and t are WFFs

if w is a WFF, Nw is a WFF

if w and x are WFFs, Kwx, Awx, Cwx, and Ewx are WFFs.

The meaning of a WFF is defined as follows:

p, q, r, s, and t are logical variables that may take on the value 0 (false) or 1 (true).

K, A, N, C, E mean and, or, not, implies, and equals as defined in the truth table below.

Definitions of K, A, N, C, and E
     w  x
  Kwx
  Awx
   Nw
  Cwx
  Ewx
  1  1
  1
  1
   0
  1
  1
  1  0
  0
  1
   0
  0
  0
  0  1
  0
  1
   1
  1
  0
  0  0
  0
  0
   1
  1
  1
A tautology is a WFF that has value 1 (true) regardless of the values of its variables. For example, ApNp is a tautology because it is true regardless of the value of p. On the other hand, ApNq is not, because it has the value 0 for p=0, q=1.
You must determine whether or not a WFF is a tautology.
Input
Input consists of several test cases. Each test case is a single line containing a WFF with no more than 100 symbols. A line containing 0 follows the last case.
Output
For each test case, output a line containing tautology or not as appropriate.
Sample Input

ApNp
ApNq
0

Sample Output

tautology
not


【 】
Waterloo Local Contest, 2006.9.30
http://poj.org/problem?id=3295
【 】
 ， 。
【 】
 ， ， 。
 。
 ac ：

#include<iostream>
#include<cstring>
#define MAX 110
using namespace std;
int a[MAX];
char str[MAX];
void calc(int p,int q,int r,int s,int t)
{
    int top=0;
    int t1,t2;
    int len=strlen(str);
    for(int i=len-1;i>=0;i--) // ， a[0]
    {
        if(str[i]=='p') a[top++]=p;
   else if(str[i]=='q') a[top++]=q;
   else if(str[i]=='r') a[top++]=r;
   else if(str[i]=='s') a[top++]=s;
   else if(str[i]=='t') a[top++]=t;

        if(str[i]=='K')
        {
           t1=a[--top];
           t2=a[--top];
           a[top++]=t1&&t2;
        }
        else if(str[i]=='A')
        {
           t1=a[--top];
           t2=a[--top];
           a[top++]=t1||t2;
        }
       else if(str[i]=='N')
        {
           t1=a[--top];
           a[top++]=!t1;
        }
       else if(str[i]=='C')
        {
           t1=a[--top];
           t2=a[--top];
           if(t1==1&&t2==0)
               a[top++]=0;
           else a[top++]=1;
        }
        else if(str[i]=='E')
        {
           t1=a[--top];
           t2=a[--top];
           if(t1==t2)
            a[top++]=1;
           else a[top++]=0;
        }
    }
}
bool judge()
{
    int p,q,r,s,t;
    for(p=0;p<2;p++)                       // 
     for(q=0;q<2;q++)
      for(r=0;r<2;r++)
       for(s=0;s<2;s++)
        for(t=0;t<2;t++)
        {
            calc(p,q,r,s,t);
            if(a[0]==0)
            {
                return false;
            }
        }
     return  true;
}
int main()
{
    while(cin>>str)
    {
        if(strcmp(str,"0")==0) break;
        if(judge())
            cout<<"tautology"<<endl;
        else cout<<"not"<<endl;
    }
}