Problem p02127 (C++) — buggy submission, verdict: Memory Limit Exceeded

#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = (int)(s); i < (int)(t); ++i)
#define each(a, b) for (auto &(a) : (b))
#define all(v) (v).begin(), (v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)), v.erase(unique(all(v)), v.end())
#define cmx(x, y) x = max(x, y)
#define cmn(x, y) x = min(x, y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout << #x << " = " << (x) << endl
#define spair(p) cout << #p << ": " << p.fi << " " << p.se << endl
#define sar(a, n)                                                              \\
  cout << #a << ":";                                                           \\
  rep(pachico, n) cout << " " << a[pachico];                                   \\
  cout << endl
#define svec(v)                                                                \\
  cout << #v << ":";                                                           \\
  rep(pachico, v.size()) cout << " " << v[pachico];                            \\
  cout << endl
#define svecp(v)                                                               \\
  cout << #v << ":";                                                           \\
  each(pachico, v) cout << " {" << pachico.first << ":" << pachico.second      \\
                        << "}";                                                \\
  cout << endl
#define sset(s)                                                                \\
  cout << #s << ":";                                                           \\
  each(pachico, s) cout << " " << pachico;                                     \\
  cout << endl
#define smap(m)                                                                \\
  cout << #m << ":";                                                           \\
  each(pachico, m) cout << " {" << pachico.first << ":" << pachico.second      \\
                        << "}";                                                \\
  cout << endl

using namespace std;

typedef pair<int, int> P;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

int n;

bool ok(string &s, string &t) {
  int pos = 0;
  rep(i, len(s)) {
    if (s[i] == t[pos]) {
      pos++;
    }
    if (pos == len(t)) {
      return true;
    }
  }
  return false;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  string s, t;
  cin >> s >> t;
  string bf = t;
  int moto = len(bf);
  n = len(s);
  int ans = 0;
  while (1) {
    if (ok(s, t)) {
      ans++;
    } else {
      break;
    }
    int k = len(t);
    if (n < (ll)k * (moto + 1) + moto) {
      break;
    }
    string nw = t;
    rep(i, moto) {
      nw += bf[i];
      nw += t;
    }
    swap(t, nw);
  }
  cout << ans << "\\n";
  return 0;
}


Error: MLE

Fixed submission:

#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = (int)(s); i < (int)(t); ++i)
#define each(a, b) for (auto &(a) : (b))
#define all(v) (v).begin(), (v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)), v.erase(unique(all(v)), v.end())
#define cmx(x, y) x = max(x, y)
#define cmn(x, y) x = min(x, y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout << #x << " = " << (x) << endl
#define spair(p) cout << #p << ": " << p.fi << " " << p.se << endl
#define sar(a, n)                                                              \\
  cout << #a << ":";                                                           \\
  rep(pachico, n) cout << " " << a[pachico];                                   \\
  cout << endl
#define svec(v)                                                                \\
  cout << #v << ":";                                                           \\
  rep(pachico, v.size()) cout << " " << v[pachico];                            \\
  cout << endl
#define svecp(v)                                                               \\
  cout << #v << ":";                                                           \\
  each(pachico, v) cout << " {" << pachico.first << ":" << pachico.second      \\
                        << "}";                                                \\
  cout << endl
#define sset(s)                                                                \\
  cout << #s << ":";                                                           \\
  each(pachico, s) cout << " " << pachico;                                     \\
  cout << endl
#define smap(m)                                                                \\
  cout << #m << ":";                                                           \\
  each(pachico, m) cout << " {" << pachico.first << ":" << pachico.second      \\
                        << "}";                                                \\
  cout << endl

using namespace std;

typedef pair<int, int> P;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

int n;

bool ok(string &s, string &t) {
  int pos = 0;
  rep(i, len(s)) {
    if (s[i] == t[pos]) {
      pos++;
    }
    if (pos == len(t)) {
      return true;
    }
  }
  return false;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  string s, t;
  cin >> s >> t;
  string bf = t;
  int moto = len(bf);
  n = len(s);
  int ans = 0;
  while (1) {
    if (ok(s, t)) {
      ans++;
    } else {
      break;
    }
    int k = len(t);
    if (n < k * (moto + 1) + moto) {
      break;
    }
    string nw = t;
    rep(i, moto) {
      nw += bf[i];
      nw += t;
    }
    swap(t, nw);
  }
  cout << ans << "\\n";
  return 0;
}