北大ACM(POJ1013-Counterfeit Dollar)

Question：http://poj.org/problem?id=1013

问题点：排除+验证。

 Memory: 244K        Time: 16MS
 Language: C++       Result: Accepted

 #include <iostream>
 #include <string>
 using namespace std;
 int flag[];//0:未出现 1:even 2:up/down
 string str[];
 int main()
 {
     int k,weight;
     cin>>k;
     while(k-->)
     {
         weight=;
         memset(flag,,sizeof(flag));
         for(int i=;i<;i++){
             cin>>str[i];
             if(i==||i==||i==)
             {
                 if(str[i]=="even")
                 {
                     for(int j=;j<str[i-].size();j++)
                     {
                         flag[str[i-].at(j)-'A']=;
                         flag[str[i-].at(j)-'A']=;
                     }
                 }else{//up down
                     for(int j=;j<str[i-].size();j++)
                     {
                         if(flag[str[i-].at(j)-'A']!=)
                         {
                             flag[str[i-].at(j)-'A']+=;
                             weight=weight>flag[str[i-].at(j)-'A']?weight:flag[str[i-].at(j)-'A'];
                         }
                         if(flag[str[i-].at(j)-'A']!=)
                         {
                             flag[str[i-].at(j)-'A']+=;
                             weight=weight>flag[str[i-].at(j)-'A']?weight:flag[str[i-].at(j)-'A'];
                         }
                     }
                 }
             }
         }
         for(int i=;i<;i++)
         {
             char c=i+'A';
             string s="";
             if(flag[i]==weight)
             {
                 for(int j=;j<;j++)
                 {
                     string t="";
                     if(str[j*+]=="up")
                     {
                         if(str[j*].find(c)!=string::npos) t="heavy.";
                         else if(str[j*+].find(c)!=string::npos) t="light.";
                     }else if(str[j*+]=="down")
                     {
                         if(str[j*].find(c)!=string::npos) t="light.";
                         else if(str[j*+].find(c)!=string::npos) t="heavy.";
                     }
                     if(s==""){
                         s=t;
                     }else if(t!="" && s!=t){
                         s="";
                         break;
                     }
                 }
                 if(s!="") cout<<c<<" is the counterfeit coin and it is "<<s<<endl;
             }
         }
     }
          return ;
 }