uva-673注意可能会给空串

#include<iostream>#include<stack>#include<cstdio>using namespace std;int n,len,ans[150];string s;int main(){    cin>>n;    getchar();    while(n--)    {        getline(cin,s);        len=s.length();        for(int i=0;i<len;i++)        {            if(s[i]=='(')ans[i]=1;            else if(s[i]==')')ans[i]=-1;            else if(s[i]=='[')ans[i]=2;            else ans[i]=-2;        }        stack<int>st;        if(len>=1)st.push(ans[0]);        for(int i=1;i<len;i++)        {            if(!st.empty()&&st.top()>0&&st.top()+ans[i]==0)st.pop();            else st.push(ans[i]);        }        if(st.empty())cout<<"Yes"<<endl;        else cout<<"No"<<endl;    }}