P8289 的第 5 个测试点和第 10 个测试点 MLE 了，但是我在洛谷 IDE 运行只占用了 564 kb。

代码如下：

#include <bits/stdc++.h>
using namespace std;
int n;
string s, k;
map<string, string> p, tmp;
map<string, bool> f, ft;
string solve(string s, bool flag) {
  if (s == k && flag) return s;
  if (ft[s]) return tmp[s];
  string name, res;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] >= '0' && s[i] <= '9') name.push_back(s[i]);
    else if (s[i] >= 'a' && s[i] <= 'z') name.push_back(s[i]);
    else if (s[i] >= 'A' && s[i] <= 'Z') name.push_back(s[i]);
    else if (s[i] == '_') name.push_back(s[i]);
    else {
      if (f[name] && !ft[name]) tmp[name] = solve(p[name], 1), ft[name] = 1, res = res + tmp[name];
      else if (f[name]) res = res + tmp[name];
      else res = res + name;
      name = "";
      res = res + s[i];
    }
  }
  if (f[name] && !ft[name]) tmp[name] = solve(p[name], 1), ft[name] = 1, res = res + tmp[name];
  else if (f[name]) res = res + tmp[name];
  else res = res + name;
  return res;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  cin >> n;
  getline(cin, s);
  for (int i = 1; i <= n; i++) {
    getline(cin, s);
    if (s[0] == '#') {
      tmp.clear(), ft.clear();
      if (s[1] == 'd') {
        string name, content;
        int j = 8;
        while (j < s.size() && s[j] != ' ') j++;
        name = s.substr(8, j - 8), content = s.substr(j + 1, s.size() - j);
        p[name] = content;
        f[name] = 1;
      }
      else {
        string name = s.substr(7, s.size() - 7);
        p[name] = "";
        f[name] = 0;
      }
    }
    else {
      string name;
      for (int i = 0; i < s.size(); i++) {
        if (s[i] >= '0' && s[i] <= '9') name.push_back(s[i]);
        else if (s[i] >= 'a' && s[i] <= 'z') name.push_back(s[i]);
        else if (s[i] >= 'A' && s[i] <= 'Z') name.push_back(s[i]);
        else if (s[i] == '_') name.push_back(s[i]);
        else {
          k = p[name];
          if (f[name] && !ft[name]) tmp[name] = solve(p[name], 0), ft[name] = 1, cout << tmp[name];
          else if (f[name]) cout << tmp[name];
          else cout << name;
          name = "";
          cout << s[i];
        }
      }
      k = p[name];
      if (f[name] && !ft[name]) tmp[name] = solve(p[name], 0), ft[name] = 1, cout << tmp[name];
      else if (f[name]) cout << tmp[name];
      else cout << name;
    }
    cout << endl;
  }
  return 0;
}

我发现是 solve 导致 MLE 了，但是我输出了 solve 的调用次数，总共只调用了 33 次。