2400.cpp

这是哈尔滨工业大学acmOJ的源代码

/* This Code is Submitted by wywcgs for Problem 2400 on 2006-10-10 at 16:12:10 */
#include <cstdio>
#include <cctype>
#include <algorithm>
using namespace std;

const int L = 128, S = 1 << 6;

int value(char*&, int);

int A(int a, int b) { return a || b; }
int K(int a, int b) { return a && b; }
int N(int a) { return !a; }
int C(int a, int b) { return (!a) || b; }
int E(int a, int b) { return a == b; }

int main()
{
	char w[L];

	while(gets(w) != NULL && w[0] != '0') {
		bool can = true;
		for(int s = 0; s < S; s++) {
			char* p = w;
			if(value(p, s) == 0) { can = false; break; }
		}
		printf(can ? "tautology\n" : "not\n");
	}
	
	return 0;
}

int value(char*& w, int s)
{
	char c = *(w++);
	if(islower(c)) return (s>>(c-'p'))&1;
	switch(c) {
	case 'K': return K(value(w, s), value(w, s));
	case 'A': return A(value(w, s), value(w, s));
	case 'N': return N(value(w, s));
	case 'C': return C(value(w, s), value(w, s));
	case 'E': return E(value(w, s), value(w, s));
	}
}