Problem p02599 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define pli pair<ll, int>
#define pil pair<int, ll>
#define pll pair<ll, ll>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
#define endl '\\n'
const int inf = 1000000007;
const ll INF = 1e18;
// int mod = 998244353;
int mod = 1000000007;
#define abs(x) (x >= 0 ? x : -(x))
#define lb(v, x) (int)(lower_bound(all(v), x) - v.begin())
#define ub(v, x) (int)(upper_bound(all(v), x) - v.begin())
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
template <typename T, typename U> T pow_(T a, U b) {
  return b ? pow_(a * a, b / 2) * (b % 2 ? a : 1) : 1;
}
ll modpow(ll a, ll b, ll _mod) {
  return b ? modpow(a * a % _mod, b / 2, _mod) * (b % 2 ? a : 1) % _mod : 1;
}
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << p.F << " " << p.S;
  return os;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  rep(i, sz(vec)) {
    if (i)
      os << " ";
    os << vec[i];
  }
  return os;
}
template <typename T> inline istream &operator>>(istream &is, vector<T> &v) {
  rep(j, sz(v)) is >> v[j];
  return is;
}
template <class T, class T2> inline void add(T &a, T2 b) {
  a += b % mod;
  if (a >= mod)
    a -= mod;
}
template <class T> void operator+=(vector<T> &v, vector<T> v2) {
  rep(i, sz(v2)) v.eb(v2[i]);
}

void solve();

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(12); // debuged
  int T;
  T = 1;
  while (T--)
    solve();
}

struct BIT { // 0 indexed
  int n;
  vector<int> bit;
  BIT(int n) : n(n) { bit.resize(n); }
  BIT(vector<int> v) {
    n = sz(v);
    bit.resize(n);
    rep(i, n) add(i, v[i]);
  }
  void add(int a, int w) {
    for (int x = a; x < n; x |= x + 1)
      bit[x] += w;
  }
  int sum(int a) { // [0, a)
    int ret = 0;
    for (int x = a - 1; x >= 0; x = (x & (x + 1)) - 1)
      ret += bit[x];
    return ret;
  }
  int sum(int a, int b) { return sum(b) - sum(a); } // [a, b)
};

// https://atcoder.jp/contests/abc174/submissions/15648035
void solve() {
  int n, q;
  cin >> n >> q;
  vector<int> c(n);
  cin >> c;

  vector<pair<pii, int>> v;
  rep(i, q) {
    int l, r;
    cin >> l >> r;
    --l;
    --r;
    v.eb(pii(r, l), i);
  }
  sort(all(v));

  vector<int> la(n + 1, -1); // lastAppeared, debuged, n+1
  BIT bit(n);
  auto out = [&]() {
    rep(i, n) cerr << bit.sum(i, i + 1) << " ";
    cerr << endl;
  };

  vector<int> ans(q); // debuged
  rep(i, q) {
    int l = v[i].F.S, r = v[i].F.F;
    // cerr << "l r " << l << " " << r << endl;
    int rb = -1;
    if (i)
      rb = v[i - 1].F.F;

    rep3(j, rb + 1, r + 1) { // rが延びた
      // cerr << "j " << j << " " << la[c[j]] << endl;
      if (la[c[j]] != -1)
        bit.add(la[c[j]], -1);
      la[c[j]] = j;
      bit.add(j, 1);
    }
    // out();
    ans[v[i].S] = bit.sum(l, r + 1);
  }
  rep(i, q) cout << ans[i] << endl;
}


Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define pli pair<ll, int>
#define pil pair<int, ll>
#define pll pair<ll, ll>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
#define endl '\\n'
const int inf = 1000000007;
const ll INF = 1e18;
// int mod = 998244353;
int mod = 1000000007;
#define abs(x) (x >= 0 ? x : -(x))
#define lb(v, x) (int)(lower_bound(all(v), x) - v.begin())
#define ub(v, x) (int)(upper_bound(all(v), x) - v.begin())
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
template <typename T, typename U> T pow_(T a, U b) {
  return b ? pow_(a * a, b / 2) * (b % 2 ? a : 1) : 1;
}
ll modpow(ll a, ll b, ll _mod) {
  return b ? modpow(a * a % _mod, b / 2, _mod) * (b % 2 ? a : 1) % _mod : 1;
}
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << p.F << " " << p.S;
  return os;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  rep(i, sz(vec)) {
    if (i)
      os << " ";
    os << vec[i];
  }
  return os;
}
template <typename T> inline istream &operator>>(istream &is, vector<T> &v) {
  rep(j, sz(v)) is >> v[j];
  return is;
}
template <class T, class T2> inline void add(T &a, T2 b) {
  a += b % mod;
  if (a >= mod)
    a -= mod;
}
template <class T> void operator+=(vector<T> &v, vector<T> v2) {
  rep(i, sz(v2)) v.eb(v2[i]);
}

void solve();

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(12); // debuged
  int T;
  T = 1;
  while (T--)
    solve();
}

struct BIT { // 0 indexed
  int n;
  vector<int> bit;
  BIT(int n) : n(n) { bit.resize(n); }
  BIT(vector<int> v) {
    n = sz(v);
    bit.resize(n);
    rep(i, n) add(i, v[i]);
  }
  void add(int a, int w) {
    for (int x = a; x < n; x |= x + 1)
      bit[x] += w;
  }
  int sum(int a) { // [0, a)
    int ret = 0;
    for (int x = a - 1; x >= 0; x = (x & (x + 1)) - 1)
      ret += bit[x];
    return ret;
  }
  int sum(int a, int b) { return sum(b) - sum(a); } // [a, b)
};

// https://atcoder.jp/contests/abc174/submissions/15647983
void solve() {
  int n, q;
  cin >> n >> q;
  vector<int> c(n);
  cin >> c;

  vector<pair<pii, int>> v;
  rep(i, q) {
    int l, r;
    cin >> l >> r;
    --l;
    --r;
    v.eb(pii(r, l), i);
  }
  sort(all(v));

  vector<int> la(n, -1); // lastAppeared
  BIT bit(n);
  auto out = [&]() {
    rep(i, n) cerr << bit.sum(i, i + 1) << " ";
    cerr << endl;
  };

  vector<int> ans(q); // debuged
  rep(i, q) {
    int l = v[i].F.S, r = v[i].F.F;
    // cerr << "l r " << l << " " << r << endl;
    int lb = -1, rb = -1;
    if (i)
      lb = v[i - 1].F.F, rb = v[i - 1].F.F;

    if (rb < r) { // rが延びた
      rep3(j, rb + 1, r + 1) {
        // cerr << "j " << j << " " << la[c[j]] << endl;
        if (la[c[j]] != -1)
          bit.add(la[c[j]], -1);
        la[c[j]] = j;
        bit.add(j, 1);
      }
    }
    // out();
    ans[v[i].S] = bit.sum(l, r + 1);
  }
  rep(i, q) cout << ans[i] << endl;
}