Problem p02571 (C++) — buggy submission, verdict: Time Limit Exceeded

// AUTHOR - NAVEEN KUMAR(@naveen19991124)
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update
// #include<boost/multiprecision/cpp_int.hpp>
// #inlcude<boost/multiprecision/cpp_dec_float.hpp>
#define ll long long
#define ld long double
#define F first
#define S second
#define nl "\\n"
#define mem(v) memset(v, 0, sizeof(v))
#define all(v) v.begin(), v.end()
#define srt(v) sort(all(v))
#define rsrt(v) sort(v.rbegin(), v.rend())
#define pb push_back
#define f(a) for (ll i = 0; i < a; i++)
#define rep(i, a, b) for (ll i = a; i < b; i++)
#define rrep(i, a, b) for (ll i = a; i > b; i--)
#define vll vector<ll>
#define pll pair<ll, ll>
#define vpll vector<pair<ll, ll>>
#define mp make_pair
#define trace(a) cout << a << "\\n";
#define trace2(a, b) cout << a << " " << b << "\\n";
#define trace3(a, b, c) cout << a << " " << b << " " << c << "\\n";
#define dbgarr(a)                                                              \\
  for (auto y : a) {                                                           \\
    cout << y << " ";                                                          \\
  }                                                                            \\
  cout << "\\n";
#define dbgparr(a)                                                             \\
  for (auto y : a) {                                                           \\
    cout << y.F << " " << y.S << "\\n";                                         \\
  }                                                                            \\
  cout << "\\n";
#define error(args...)                                                         \\
  {                                                                            \\
    string _s = #args;                                                         \\
    replace(_s.begin(), _s.end(), ',', ' ');                                   \\
    stringstream _ss(_s);                                                      \\
    istream_iterator<string> _it(_ss);                                         \\
    err(_it, args);                                                            \\
  }
#define hell 1000000007
#define INF (ll)(1e18 + 5)
#define fast                                                                   \\
  ios_base::sync_with_stdio(false);                                            \\
  cin.tie(NULL);                                                               \\
  cout.tie(NULL);
using namespace std;
using namespace std::chrono;
using namespace __gnu_pbds;
// using boost :: multiprecision :: cpp_int;
// using boost :: multiprecision :: cpp_dec_float_50;
// using boost :: multiprecision :: cpp_dec_float_100;

// Ordered Sets
typedef tree<ll, null_type, less<ll>, rb_tree_tag,
             tree_order_statistics_node_update>
    ordered_set;
// find_by_order() // Value at given index 0-based
// order_of_key() // Index returned where element is to be
// inserted(lower_bound())(if present return index)

// Debug section
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  err(++it, args...);
}
void out(vector<ll> arr) {
  for (auto i : arr) {
    cout << i << " ";
  }
  cout << "\\n";
}
void out(vector<pair<ll, ll>> par) {
  for (auto i : par) {
    cout << i.F << " " << i.S << "\\n";
  }
}
void out(set<ll> arr) {
  for (auto i : arr) {
    cout << i << " ";
  }
  cout << "\\n";
}
void out(multiset<ll> arr) {
  for (auto i : arr) {
    cout << i << " ";
  }
  cout << "\\n";
}

// Power functions
ll power(ll a, ll n) {
  ll p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
    }
    n >>= 1;
    a *= a;
  }
  return p;
}
ll power(ll a, ll n, ll mod) {
  ll p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
      p %= mod;
    }
    n >>= 1;
    a *= a;
    a %= mod;
  }
  return p % mod;
}

// Mod functions
ll modInverse(ll a, ll m) {
  ll m0 = m;
  ll y = 0, x = 1;
  if (m == 1) {
    return 0;
  }
  while (a > 1) {
    ll q = a / m;
    ll t = m;
    m = a % m, a = t;
    t = y;
    y = x - q * y;
    x = t;
  }
  if (x < 0) {
    x += m0;
  }
  return x;
}

inline ll add(ll a, ll b) {
  return (((a >= hell) ? a % hell : a) + ((b >= hell) ? b % hell : b) + hell) %
         hell;
}
inline ll subt(ll a, ll b) { return (a - b + hell) % hell; }
inline ll mult(ll a, ll b) {
  return (1ll * ((a >= hell) ? a % hell : a) * ((b >= hell) ? b % hell : b)) %
         hell;
}

// Miscellaneous
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }

ll lcm(ll a, ll b) { return a * (b / gcd(a, b)); }

ll mylog(ll n, ll b) {
  ll i = 1;
  ll ans = 0;
  while (1) {
    if (i > n / b) {
      break;
    }
    i = i * b;
    ans++;
  }
  return ans;
}

// Comparators
bool compare(const pair<ll, ll> &a, const pair<ll, ll> &b) {
  if (a.first == b.first) {
    return a.second < b.second;
  }
  return a.first < b.first;
}

bool comparerev(const pair<ll, ll> &a, const pair<ll, ll> &b) {
  if (a.first == b.first) {
    return a.second > b.second;
  }
  return a.first > b.first;
}
const ll d4i[4] = {-1, 0, 1, 0}, d4j[4] = {0, 1, 0, -1};
const ll d8i[8] = {-1, -1, 0, 1, 1, 1, 0, -1},
         d8j[8] = {0, 1, 1, 1, 0, -1, -1, -1};

// MAIN CODE
int main() {
  fast ll t = 1;
  //  cin>>t;
  while (t--) {
    string s1, s2;
    cin >> s1 >> s2;
    ll ans = INF;
    ll sum = 0;
    for (ll i = 0; i <= s1.length() - s2.length(); i++) {
      sum = 0;
      string x = s1.substr(i, s2.length());
      for (ll i = 0; i < s2.length(); i++) {
        if (x[i] != s2[i]) {
          sum++;
        }
      }
      ans = min(ans, sum);
    }
    cout << ans << "\\n";
  }
  return 0;
}


Error: TLE

Fixed submission:

// AUTHOR - NAVEEN KUMAR(@naveen19991124)
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update
// #include<boost/multiprecision/cpp_int.hpp>
// #inlcude<boost/multiprecision/cpp_dec_float.hpp>
#define ll long long
#define ld long double
#define F first
#define S second
#define nl "\\n"
#define mem(v) memset(v, 0, sizeof(v))
#define all(v) v.begin(), v.end()
#define srt(v) sort(all(v))
#define rsrt(v) sort(v.rbegin(), v.rend())
#define pb push_back
#define f(a) for (ll i = 0; i < a; i++)
#define rep(i, a, b) for (ll i = a; i < b; i++)
#define rrep(i, a, b) for (ll i = a; i > b; i--)
#define vll vector<ll>
#define pll pair<ll, ll>
#define vpll vector<pair<ll, ll>>
#define mp make_pair
#define trace(a) cout << a << "\\n";
#define trace2(a, b) cout << a << " " << b << "\\n";
#define trace3(a, b, c) cout << a << " " << b << " " << c << "\\n";
#define dbgarr(a)                                                              \\
  for (auto y : a) {                                                           \\
    cout << y << " ";                                                          \\
  }                                                                            \\
  cout << "\\n";
#define dbgparr(a)                                                             \\
  for (auto y : a) {                                                           \\
    cout << y.F << " " << y.S << "\\n";                                         \\
  }                                                                            \\
  cout << "\\n";
#define error(args...)                                                         \\
  {                                                                            \\
    string _s = #args;                                                         \\
    replace(_s.begin(), _s.end(), ',', ' ');                                   \\
    stringstream _ss(_s);                                                      \\
    istream_iterator<string> _it(_ss);                                         \\
    err(_it, args);                                                            \\
  }
#define hell 1000000007
#define INF (ll)(1e18 + 5)
#define fast                                                                   \\
  ios_base::sync_with_stdio(false);                                            \\
  cin.tie(NULL);                                                               \\
  cout.tie(NULL);
using namespace std;
using namespace std::chrono;
using namespace __gnu_pbds;
// using boost :: multiprecision :: cpp_int;
// using boost :: multiprecision :: cpp_dec_float_50;
// using boost :: multiprecision :: cpp_dec_float_100;

// Ordered Sets
typedef tree<ll, null_type, less<ll>, rb_tree_tag,
             tree_order_statistics_node_update>
    ordered_set;
// find_by_order() // Value at given index 0-based
// order_of_key() // Index returned where element is to be
// inserted(lower_bound())(if present return index)

// Debug section
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  err(++it, args...);
}
void out(vector<ll> arr) {
  for (auto i : arr) {
    cout << i << " ";
  }
  cout << "\\n";
}
void out(vector<pair<ll, ll>> par) {
  for (auto i : par) {
    cout << i.F << " " << i.S << "\\n";
  }
}
void out(set<ll> arr) {
  for (auto i : arr) {
    cout << i << " ";
  }
  cout << "\\n";
}
void out(multiset<ll> arr) {
  for (auto i : arr) {
    cout << i << " ";
  }
  cout << "\\n";
}

// Power functions
ll power(ll a, ll n) {
  ll p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
    }
    n >>= 1;
    a *= a;
  }
  return p;
}
ll power(ll a, ll n, ll mod) {
  ll p = 1;
  while (n > 0) {
    if (n % 2) {
      p = p * a;
      p %= mod;
    }
    n >>= 1;
    a *= a;
    a %= mod;
  }
  return p % mod;
}

// Mod functions
ll modInverse(ll a, ll m) {
  ll m0 = m;
  ll y = 0, x = 1;
  if (m == 1) {
    return 0;
  }
  while (a > 1) {
    ll q = a / m;
    ll t = m;
    m = a % m, a = t;
    t = y;
    y = x - q * y;
    x = t;
  }
  if (x < 0) {
    x += m0;
  }
  return x;
}

inline ll add(ll a, ll b) {
  return (((a >= hell) ? a % hell : a) + ((b >= hell) ? b % hell : b) + hell) %
         hell;
}
inline ll subt(ll a, ll b) { return (a - b + hell) % hell; }
inline ll mult(ll a, ll b) {
  return (1ll * ((a >= hell) ? a % hell : a) * ((b >= hell) ? b % hell : b)) %
         hell;
}

// Miscellaneous
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }

ll lcm(ll a, ll b) { return a * (b / gcd(a, b)); }

ll mylog(ll n, ll b) {
  ll i = 1;
  ll ans = 0;
  while (1) {
    if (i > n / b) {
      break;
    }
    i = i * b;
    ans++;
  }
  return ans;
}

// Comparators
bool compare(const pair<ll, ll> &a, const pair<ll, ll> &b) {
  if (a.first == b.first) {
    return a.second < b.second;
  }
  return a.first < b.first;
}

bool comparerev(const pair<ll, ll> &a, const pair<ll, ll> &b) {
  if (a.first == b.first) {
    return a.second > b.second;
  }
  return a.first > b.first;
}
const ll d4i[4] = {-1, 0, 1, 0}, d4j[4] = {0, 1, 0, -1};
const ll d8i[8] = {-1, -1, 0, 1, 1, 1, 0, -1},
         d8j[8] = {0, 1, 1, 1, 0, -1, -1, -1};

// MAIN CODE
int main() {
  fast ll t = 1;
  //  cin>>t;
  while (t--) {
    string s1, s2;
    cin >> s1 >> s2;
    ll ans = INF;
    ll sum = 0;
    for (ll i = s2.length() - 1; i < s1.length(); i++) {
      sum = 0;
      ll ind = s2.length() - 1;
      for (ll j = i; j >= i - s2.length() + 1; j--) {
        if (s1[j] != s2[ind]) {
          sum++;
        }
        ind--;
      }
      ans = min(ans, sum);
    }
    cout << ans << "\\n";
  }
  return 0;
}