運算式題 ： poj 2269 && ＳＧＵ １８２

運算式資料

http://www.engr.mun.ca/~theo/Misc/exp_parsing.htm

學過編譯原理的話對這種運算式怎麼算還是小兒科的吧

但是，手算會算，不代表代碼可以寫的好。。。。

這種題沒怎麼寫，調試了ｎ久

ＳＧＵ　１８２

/*運算式計算，我用的是棧版本 狀態壓縮枚舉每個字母是0或1，判斷原來運算式的值是否為true ， 為true就輸出這個狀態一些有關題意重要的資訊請看forum*/#include<cstdio>#include<cstring>const int N = 3010;int mp[256];template<typename T>  struct Exp{    bool error;    int tot,top;    T num[N];    char op[N];    void init()    {        error=false;        tot=0;        top=0;        op[1]='(';    }    bool prior(char a,char b)    {        if(b=='|' || b=='<' || b=='=' || b=='#')        {            return a!='(';        }        if(b=='&')  return a=='!' || a=='&';        return false;    }    T calc(char c,T a, T b)    {        if(c=='&') return a && b;        if(c=='|') return a || b;        if(c=='<') return a == b;        if(c=='=') return!a || b;        if(c=='#') return a ^ b;    }    T solve(char *s,int state)    {        int len = strlen(s);        s[len++]=')';        for(int i=0; i<len; i++)        {            if(s[i]=='(') op[++top]=s[i];            else if(s[i]==')')            {                while(top>0&&op[top]!='(')                {                    if(op[top]=='!')                    {                        num[tot]=!num[tot];                        top--;                    }                    else                    {                        num[tot-1] = calc(op[top],num[tot-1],num[tot]);                        tot--;                        top--;                    }                }                top--;            }            else if(s[i] >= 'a' && s[i] <= 'j')            {                int x = mp[s[i]];                num[++tot] =( ((1<<x)&state) > 0 );            }            else            {                while(top>0&&prior(op[top],s[i]))                {                    if(op[top]=='!'){                        num[tot]=!num[tot];                        top--;                    }                    else {                         num[tot-1] = calc(op[top],num[tot-1],num[tot]);                         tot--;                         top--;                    }                }                op[++top]=s[i];            }            if(s[i]=='|' || s[i]=='=') i++;            else if(s[i]=='<') i+=2;        }        return num[1];    }};Exp<bool> E;char s[N];int main(){    while(gets(s)){memset(mp,-1,sizeof(mp));int m = 0 , len = strlen(s);char rec[15];for(int i = 0; i < len; i++){if(s[i] >= 'a' && s[i] <= 'j' && mp[s[i]] < 0){rec[m] = s[i];mp[s[i]] = m++;}}bool has = false;for(int i = 0; i < (1<<m); i++){E.init();if(E.solve(s,i)){if(has) printf("||");else has = true;for(int j = 0; j < m; j++){if(j) printf("&");if(!(i&(1<<j))) printf("!");printf("%c",rec[j]);}}}if(!has) printf("a&!a");printf("\n");}    return 0;}

ｐｏｊ　２２６９

#include<cstdio>#include<cstring>#include<string>#include<set>#include<iostream>using namespace std;const int N = 500;template<typename T>  struct Exp{    bool error;    int tot,top;    T num[N];    char op[N];    void init()    {        error=false;        tot=0;        top=1;        op[1]='(';    }    bool prior(char a,char b)    {      if(b=='+' || b=='-') return a != '(';  return a=='*';    }    T calc(char c,T a, T b)    {   string ans="";   set<char> st;       if(c=='+')   {   for(int i = 0; i < a.length(); i++) st.insert(a[i]);   for(int i = 0; i < b.length(); i++) st.insert(b[i]);   for(set<char>::iterator it = st.begin();it!=st.end();it++)   {   ans += *it;   }   return ans;   }   if(c=='-')   {   for(int i = 0; i < a.length(); i++) st.insert(a[i]);   for(int i = 0; i < b.length(); i++) if(st.find(b[i])!=st.end()) st.erase(b[i]);   for(set<char>::iterator it = st.begin();it!=st.end();it++)   {   ans += *it;   }   return ans;   }   if(c=='*')   {   for(int i = 0; i < a.length(); i++) st.insert(a[i]);   for(int i = 0; i < b.length(); i++) if(st.find(b[i])!=st.end()) ans+=b[i];   return ans;   }    }    T solve(char *s)    {        int len = strlen(s);        s[len++]=')';        for(int i=0; i<len; i++)        {            if(s[i]=='(') op[++top]=s[i];            else if(s[i]==')')            {                while(top>0&&op[top]!='(')                {                        num[tot-1] = calc(op[top],num[tot-1],num[tot]);                        tot--;                        top--;                }                top--;            }            else if(s[i] == '{')            { i++; if(s[i]== '}')  { num[++tot]=""; continue; } string tmp = "";                 while(i<len && s[i] >= 'A' && s[i] <= 'Z') {// printf("i=%d\n",i); tmp += s[i]; i++; }  num[++tot] = tmp;// printf("tot=%d\n",tot);// cout<<"dd"<<tmp<<endl;            }            else            {                while(top>0&&prior(op[top],s[i]))                {                         num[tot-1] = calc(op[top],num[tot-1],num[tot]);                         tot--;                         top--;                }                op[++top]=s[i];            }        }        return num[tot];    }};Exp<string> E;char s[N];int main(){    while(gets(s)){E.init();cout<<"{"<<E.solve(s)<<"}"<<endl;}    return 0;}