Portal: http://codeforces.com/problemset/problem/190/C
一道卡输入输出的蛋疼题
题意：给你一个由pair和int所组成的沙茶字符串(最大含有1e5个单词)，输出合法的pair序列
这道题可以拿栈做，也就是vector或stack
呵呵 (vector==stack)=1
Examples
Input
3
pair pair int int int
Output
pair<pair<int,int>,int>
1 #include<iostream> 2 #include<cstring> 3 #include<sstream> 4 #include<vector> 5 using namespace std; 6 #define FOR(i,j,k) for(int i=j;i<=k;i++) 7 #define FORD(i,j,k) for(int i=j;i>=k;i--) 8 #define maxn 100010 9 #define SZ(x) int(x.size()) 10 int k; 11 int a[maxn]; 12 pair<int,int> res[maxn]; 13 vector<int> zz; 14 string s; 15 stringstream ss,ans; 16 void cq(int l) 17 { 18 if(a[l]) 19 { 20 ans<<"pair<"; 21 cq(res[l].first); 22 ans<<','; 23 cq(res[l].second); 24 ans<<'>'; 25 } 26 else ans<<"int"; 27 return; 28 } 29 int main() 30 { 31 getline(cin,s); 32 getline(cin,s); 33 ss<<s; 34 while(!ss.eof()) 35 { 36 ss>>s; 37 a[++k]=(s=="pair"); 38 } 39 FORD(i,k,1) 40 { 41 if(a[i]) 42 { 43 if(SZ(zz)<2) 44 { 45 cout<<"Error occurred"<<endl; 46 return 0; 47 } 48 res[i].first=zz.back(); 49 zz.pop_back(); 50 res[i].second=zz.back(); 51 zz.pop_back(); 52 } 53 zz.push_back(i); 54 } 55 if(SZ(zz)>1) { 56 cout<<"Error occurred"<<endl; 57 return 0; 58 } 59 cq(1); 60 cout<<ans.str(); 61 return 0; 62 }
然后除了这个反人类的倒着处理我还写了个正着来的
1 #include<iostream> 2 #include<cstring> 3 #include<sstream> 4 using namespace std; 5 #define FOR(i,j,k) for(int i=j;i<=k;i++) 6 #define FORD(i,j,k) for(int i=j;i>=k;i--) 7 #define maxn 100010 8 #define SZ(x) int(x.size()) 9 string s; 10 stringstream ss,ans; 11 bool cq() 12 { 13 if(ss.eof()) return false; 14 ss>>s; 15 if(s=="pair") 16 { 17 ans<<"pair<"; 18 if(!cq()) return false; 19 ans<<','; 20 if(!cq()) return false; 21 ans<<'>'; 22 } 23 else ans<<"int"; 24 return true; 25 } 26 27 int main() 28 { 29 getline(cin,s); 30 getline(cin,s); 31 ss<<s; 32 if(cq()&&ss.eof()) cout<<ans.str(); else cout<<"Error occurred"<<endl; 33 return 0; 34 }
总之就是各种sstream大法好啦~
#include<sstream> stringstream ss; ss<<s; ss>>s; ss.eof()