Problem p02763 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define REP(a, b) for (int a = 0; a < (b); ++a)
#define REP1(i, n) for (int i = 1; i <= (n); ++i)
#define debug(x) cerr << #x << ": " << x << '\n'
#define all(x) (x).begin(), (x).end()
#define YES() printf("YES\n")
#define NO() printf("NO\n")
#define isYES(x) printf("%s\n", (x) ? "YES" : "NO")
#define Yes() printf("Yes\n")
#define No() printf("No\n")
#define isYes(x) printf("%s\n", (x) ? "Yes" : "No")
#define isPossible(x) printf("%s\n", (x) ? "Possible" : "Impossible")
#define SZ(x) ((int)(x).size())
#define pb push_back
#define mp make_pair
#define INF (1 << 29)

// const long long INF = 1LL<<60;

#define Sp(p) cout << setprecision(25) << fixed << p << endl
#define vi vector<int>
#define vl vector<ll>
#define vii vector<vector<int>>
#define vll vector<vector<ll>>
#define vs vector<string>
#define pii pair<int, int>
#define pis pair<int, string>
#define psi pair<string, int>
#define pll pair<ll, ll>
#define pie 3.14159265358979323846
using namespace std;
typedef pair<int, int> P;
typedef pair<ll, ll> LP;
typedef pair<int, P> PP;
typedef pair<ll, LP> LPP;
template <class T = int> T in() {
  T x;
  cin >> x;
  return (x);
}
template <class T> void print(T &x) { cout << x << '\n'; }

const int MOD = (int)1e9 + 7;
// const int mod =(int)998244353;
const int mod = (int)1e9 + 7;

const int MAX = 510000;
ll fac[MAX], finv[MAX], inv[MAX];
void COMint() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
ll COM(int n, int k) {
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
ll gcd(ll a, ll b) {
  if (a < 0)
    a = -a;
  if (b < 0)
    b = -b;
  if (b == 0)
    return a;
  if (a > b) {
    swap(a, b);
  }
  return gcd(a, b % a);
}
ll lcm(ll a, ll b) {
  if (a < 0)
    a = -a;
  if (b < 0)
    b = -b;
  ll g;
  g = gcd(a, b);
  return b / g * a;
}
bool compare_by_b(pair<int, int> a, pair<int, int> b) {
  if (a.second != b.second) {
    return a.second < b.second;
  } else {
    return a.first < b.first;
  }
}
bool compare_by_a(pair<int, int> a, pair<int, int> b) {
  if (a.first != b.first) {
    return a.first < b.first;
  } else {
    return a.second < b.second;
  }
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
ll RS(ll N, ll P, ll m) {
  if (P == 0) {
    return 1;
  } else {
    if (P % 2 == 0) {
      ll t = RS(N, P / 2, m);
      return t * t % m;
    } else {
      return N * RS(N, P - 1, m) % m;
    }
  }
}
bool greater_pair(pair<ll, ll> a, pair<ll, ll> b) {
  if (a.first != b.first) {
    return a.first > b.first;
  } else {
    return a.second > b.second;
  }
}

int main() {
  ios::sync_with_stdio(false);
  int N = in();
  string S;
  cin >> S;
  int Q = in();
  vector<set<int>> v(26);
  REP(i, N) { v[S[i] - 'a'].insert(i + 1); }
  REP(i, Q) {
    int type = in();
    if (type == 1) {
      int iq;
      string cq;
      cin >> iq >> cq;
      REP(i, 26) {
        if (v[i].find(iq) != v[i].end()) {
          v[i].erase(iq);
          break;
        }
      }
      v[cq[0] - 'a'].insert(iq);
    } else {
      int l, r;
      cin >> l >> r;
      int ans = 0;
      REP(i, 26) {
        int temp = *lower_bound(all(v[i]), l);
        if (temp >= l && temp <= r) {
          ans++;
        }
      }
      cout << ans << endl;
    }
  }
  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define REP(a, b) for (int a = 0; a < (b); ++a)
#define REP1(i, n) for (int i = 1; i <= (n); ++i)
#define debug(x) cerr << #x << ": " << x << '\n'
#define all(x) (x).begin(), (x).end()
#define YES() printf("YES\n")
#define NO() printf("NO\n")
#define isYES(x) printf("%s\n", (x) ? "YES" : "NO")
#define Yes() printf("Yes\n")
#define No() printf("No\n")
#define isYes(x) printf("%s\n", (x) ? "Yes" : "No")
#define isPossible(x) printf("%s\n", (x) ? "Possible" : "Impossible")
#define SZ(x) ((int)(x).size())
#define pb push_back
#define mp make_pair
#define INF (1 << 29)

// const long long INF = 1LL<<60;

#define Sp(p) cout << setprecision(25) << fixed << p << endl
#define vi vector<int>
#define vl vector<ll>
#define vii vector<vector<int>>
#define vll vector<vector<ll>>
#define vs vector<string>
#define pii pair<int, int>
#define pis pair<int, string>
#define psi pair<string, int>
#define pll pair<ll, ll>
#define pie 3.14159265358979323846
using namespace std;
typedef pair<int, int> P;
typedef pair<ll, ll> LP;
typedef pair<int, P> PP;
typedef pair<ll, LP> LPP;
template <class T = int> T in() {
  T x;
  cin >> x;
  return (x);
}
template <class T> void print(T &x) { cout << x << '\n'; }

const int MOD = (int)1e9 + 7;
// const int mod =(int)998244353;
const int mod = (int)1e9 + 7;

const int MAX = 510000;
ll fac[MAX], finv[MAX], inv[MAX];
void COMint() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
ll COM(int n, int k) {
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
ll gcd(ll a, ll b) {
  if (a < 0)
    a = -a;
  if (b < 0)
    b = -b;
  if (b == 0)
    return a;
  if (a > b) {
    swap(a, b);
  }
  return gcd(a, b % a);
}
ll lcm(ll a, ll b) {
  if (a < 0)
    a = -a;
  if (b < 0)
    b = -b;
  ll g;
  g = gcd(a, b);
  return b / g * a;
}
bool compare_by_b(pair<int, int> a, pair<int, int> b) {
  if (a.second != b.second) {
    return a.second < b.second;
  } else {
    return a.first < b.first;
  }
}
bool compare_by_a(pair<int, int> a, pair<int, int> b) {
  if (a.first != b.first) {
    return a.first < b.first;
  } else {
    return a.second < b.second;
  }
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
ll RS(ll N, ll P, ll m) {
  if (P == 0) {
    return 1;
  } else {
    if (P % 2 == 0) {
      ll t = RS(N, P / 2, m);
      return t * t % m;
    } else {
      return N * RS(N, P - 1, m) % m;
    }
  }
}
bool greater_pair(pair<ll, ll> a, pair<ll, ll> b) {
  if (a.first != b.first) {
    return a.first > b.first;
  } else {
    return a.second > b.second;
  }
}

int main() {
  ios::sync_with_stdio(false);
  int N = in();
  string S;
  cin >> S;
  int Q = in();
  vector<set<int>> v(26);
  REP(i, N) { v[S[i] - 'a'].insert(i + 1); }
  REP(i, Q) {
    int type = in();
    if (type == 1) {
      int iq;
      string cq;
      cin >> iq >> cq;
      REP(i, 26) {
        if (v[i].find(iq) != v[i].end()) {
          v[i].erase(iq);
          break;
        }
      }
      v[cq[0] - 'a'].insert(iq);
    } else {
      int l, r;
      cin >> l >> r;
      int ans = 0;
      REP(i, 26) {
        auto temp = v[i].lower_bound(l);
        if (temp != v[i].end() && *temp <= r) {
          ans++;
        }
      }
      cout << ans << endl;
    }
  }
  return 0;
}