POJ3295 Tautology 解题报告

#include <iostream>
#include <string>
#include <stack>
#define  Det 112
using namespace std;
int val[5];
string st;
stack<int> inte;
int main() {
int len, k, m, x, y;
while (cin >> st) {
if (st[0] == '0') return 0;
for (int n = 0; n <= 31; n++) {
for (int i = 0, p = n; i <= 4; i++, p >>= 1) val[i] = p & 1;
len = st.length();
for (int i = len - 1; i >= 0; i--) {
if (st[i] >= Det) inte.push (val[st[i] - Det]);
else if (st[i] == 'N') {
x = inte.top(); inte.pop();
inte.push (!x);
}
else {
x = inte.top(); inte.pop();
y = inte.top(); inte.pop();
if (st[i] == 'K')  x = x & y;
if (st[i] == 'A')  x = x | y;
if (st[i] == 'C')  x = (x<=y);
if (st[i] == 'E')  x = (x ==y);
inte.push (x);
}
}
if (inte.top() == 0) {
cout << "not" << endl;
break;
}
else if (n == 31) cout << "tautology" << endl;
}
}
return 0;
}