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…

[POJ3295]Tautology 试题描述 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 follow…

题目链接. 分析: 最多有五个变量,所以枚举所有的真假值,从后向前借助于栈验证是否为永真式. #include <iostream> #include <cstring> #include <cstdio> #include <cstdlib> #include <stack> using namespace std; + ; stack<bool> S; char s[maxn]; ], ans; void check(char p…

题目链接:http://poj.org/problem?id=3295 题意: 输入由p.q.r.s.t.K.A.N.C.E共10个字母组成的逻辑表达式, 其中p.q.r.s.t的值为1(true)或0(false),即逻辑变量: K.A.N.C.E为逻辑运算符, K --> and:  x && y A --> or:  x || y N --> not :  !x C --> implies :  (!x)||y E --> equals :  x==y…

Tautology 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 followin…

https://vjudge.net/problem/POJ-3295 题意 有五种运算符和五个参数,现在给你一个不超过100字符的算式,问最后结果是否恒为1? 分析 首先明确各运算符的意义,K(&&),A(||),N(!),E(==),C特殊判断一下.计算的话肯定是从后往前的,遇到变量进栈,遇到运算符则出栈做运算.现在的问题是各个变量的数值未知,由于只有5个变量,总共只有32总可能,所以暴力跑一遍即可,每种取值都试一次. #include<iostream> #include…

Tautology 思路很简单,对于p.q.r.s.t暴力枚举是0还是1,判断即可.判断时像写表达式求值那样用栈.为了方便可以从后往前,因为最后一个肯定不是运算.那几个奇奇怪怪的函数可以找规律然后转为位运算,简洁又快. #include<cstdio> #include<stack> #include<cstring> using namespace std; const int MAXN=105; char a[MAXN]; int n,p,q,r,s,t; bool…

题目链接:http://poj.org/problem?id=3295 思路分析:判断逻辑表达式是否为永真式问题.根据该表达式的特点,逻辑词在逻辑变量前,类似于后缀表达式求值问题. 算法中使用两个栈,从表达式的后边开始处理表达式中每个字符:若为逻辑变量,使其入栈SR,否则从栈SR中弹出两个逻辑变量, 进行运算后的结果再入栈SR:直到处理完表达式所有的字符.(PS:使用栈可以很好的处理广义表类似的序列) 代码如下: #include <iostream> #include <stack&g…

给你一个表达式,其包括一些0,1变量和一些逻辑运算法,让你推断其是否为永真式. 计算表达式的经常使用两种方法:1.递归: 2.利用栈. code(递归实现) #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #include <string> using namespace std; char str[2000]; int pos; bool ca…

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…