zoj1094-Matrix Chain Multiplication

#include<iostream>#include<stack>using namespace std;struct node{char ch;int a,b;};node arr[27];int main(){stack<node> sta;int num,k=0;cin>>num;while(num--){cin>>arr[k].ch>>arr[k].a>>arr[k].b;k++;}char ch;int sum=0;cin.get();while(cin.get(ch)){if(ch=='\n'){if(!sta.empty()){while(!sta.empty())sta.pop();cout<<sum<<endl;}sum=0;continue;}if(ch=='(')continue;if(ch==')'){if(sta.size()==1){cout<<sum<<endl;cin.get();continue;}node t1,t2;t1=sta.top();sta.pop();t2=sta.top();sta.pop();if(t2.b!=t1.a){cout<<"error"<<endl;while(!sta.empty())sta.pop();sum=0;cin.get();continue;}node temp;temp.a=t2.a;temp.b=t1.b;sta.push(temp);sum+=t2.a*t1.a*t1.b;}for(int i=0;i<k;i++){if(arr[i].ch==ch){sta.push(arr[i]);break;}}}return 0;}