太囧了，刚开始我居然把

        while(!s.empty()) s.pop();

        while(!q.empty()) q.pop();

写成了

        if(!s.empty()) s.pop();

        if(!q.empty()) q.pop();

害我WA了十多次，浪费了不少时间。幸亏在论坛上发帖了，多谢这位兄弟发现了，再次感谢

Problem : 1022 ( Train Problem I ) Judge Status : Accepted RunId : 5628664 Language : C++ Author : ssun Code Render Status : Rendered By HDOJ C++ Code Render Version 0.01 Beta #include<cstdio> #include<stack> #include<queue> #include<string> #include<iostream> using namespace std; int main() { stack<char> s; queue<string> q; char s1[110],s2[110]; int n; while(scanf("%d",&n)!= EOF) { //getchar(); while(!s.empty()) s.pop(); while(!q.empty()) q.pop(); scanf("%s%s",s1,s2); //cout<<strlen(s1)<<endl; //printf("%s\n%s",s1,s2); int k=0; int i=0; while(i<=n) { if(!s.empty()&&s.top()==s2[k]) { while(!s.empty()&&s.top()==s2[k]) { s.pop(); q.push("out"); k++; } if(k>=n) break; //i--; } else if(i==n) break; else { s.push(s1[i]); q.push("in"); i++; } } if(k>=n) { puts("Yes."); while(!q.empty()) { cout<<q.front()<<endl; q.pop(); } } else puts("No."); puts("FINISH"); } return 0; }