poj 3295 Tautology

http://poj.org/problem?id=3295

代码：

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<vector>
#include<set>
#include<map>
#include<string>
#include<queue>
#include<stack>
#include <iomanip>
using namespace std;
#define LL long long
#define sint short int
const int INF=0x3f3f3f3f;
//priority_queue<int,vector<int>,greater<int> >qt;
bool a[7];
bool ans;
string s;
bool K(char k,bool t1)
{
    return (!t1);
}
bool K(char k,bool t1,bool t2)
{
    if(k=='K')
    return (t1&&t2);
    if(k=='A')
    return (t1||t2);
    if(k=='C')
    return ((!t1)||t2);
    if(k=='E')
    return (t1==t2);
    return true;
}
void test()
{
    stack<bool>st;
    for(int i=s.length()-1;i>=0;--i)
    {
        if(s[i]<='t'&&s[i]>='p')
        st.push(a[s[i]-'p']);
        else
        {
            bool tmp1,tmp2;
            if(s[i]=='N')
            {
                tmp1=st.top();st.pop();
                st.push(K(s[i],tmp1));
            }else
            {
                tmp1=st.top();st.pop();
                tmp2=st.top();st.pop();
                st.push(K(s[i],tmp1,tmp2));
            }
        }
    }
    if(st.top()==false)
    ans=st.top();
}
void dfs(int x)
{
    if(x==5)
    {test();return ;}
    a[x]=true;
    dfs(x+1);
    a[x]=false;
    dfs(x+1);
    if(ans==false)
    return ;
}
int main()
{
    //freopen("data.in","r",stdin);
    while(cin>>s)
    {
        if(s=="0")
        break;
        ans=true;
        dfs(0);
        if(ans)
        cout<<"tautology"<<endl;
        else
        cout<<"not"<<endl;
    }
    return 0;
}