简单模拟题目。

使用 $set$ 去重， $stack$ 统计，再加上一些细节就好了。

#include<bits/stdc++.h>
using namespace std;
const int N=10001;
struct Node {
    char name;
    int type,level;                                 
}; 
int str2int(string s) {
    int ret=0,i=0;
    while(s[i]>='0'&&s[i]<='9') {
        ret=ret*10+s[i]-'0';
        i++;
    }
    return ret;
}
void splitstr(string s, char &ch, int &st, int &ed) {
    stringstream ss;
    string n1,n2;
    ss<<s.substr(2);                                   
    ss>>ch;
    ss>>n1;
    if(n1[0]=='n') st=N;
    else st=str2int(n1);
    ss>>n2;
    if(n2[0]=='n') ed=N;
    else ed=str2int(n2);
}
int main() {
    int ntests;
    cin>>ntests;
    while(ntests--) {
        int len,exp,level=0,cnt=0,ans=0;
        string expr,line;
        stack<Node> stk;
        set<char> vname;
        int ERR=0;                                  
        cin>>len>>expr; cin.get();                  
        if(expr[2]=='1') exp=0;                     
        else exp=str2int(expr.substr(4));           
        for(int i=0;i<len;i++) {
            getline(cin,line);
            if(line[0]=='F') {                      
                char vn; int st,ed,type;
                splitstr(line,vn,st,ed);
                if(vname.count(vn)>0) ERR=2;        
                vname.insert(vn);                  
                if(st>ed) 
                    type=0,level=0;
                else if(st<ed&&ed==N)                
                    type=1,level++;        
                else type=2;
                stk.push((Node){vn,type,level});
            } else if(line[0]=='E') {                
                if(stk.empty()) {ERR=1; continue;}  
                Node cur=stk.top(); stk.pop();    
                vname.erase(cur.name);            
                if(cur.type==0) cnt=0;
                else if(cur.type==1) {
                    level=cur.level-1;
                    cnt=max(cnt,cur.level);        
                }
                if(stk.empty()) ans=max(ans,cnt);
            }
        }
        if(!stk.empty()) ERR=1;
        if(ERR>0) cout<<"ERR"<<endl;
        else if(ans==exp) cout<<"Yes"<<endl;
        else cout<<"No"<<endl;
    }
    return 0;
}