Problem p02770 (C++)

Buggy submission (status: 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 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()
const int inf = 1e9 + 7;
const ll INF = 1e18;
#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;
}
template <typename T> T gcd(T a, T b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
template <typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template <typename T> T pow(T a, int b) {
  return b ? pow(a * a, b / 2) * (b % 2 ? a : 1) : 1;
}
const int mod = 1000000007;
ll modpow(ll a, int b) {
  return b ? modpow(a * a % mod, b / 2) * (b % 2 ? a : 1) % mod : 1;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  for (auto &vi : vec)
    os << vi << " ";
  return os;
}
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << p.F << " " << p.S;
  return os;
}
template <class T> inline void add(T &a, int b) {
  a += b;
  if (a >= mod)
    a -= mod;
}

void solve();

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  int T;
  // cin >> T;
  T = 1;

  while (T--) {
    solve();
  }
}

void solve() {
  int K, q;
  cin >> K >> q;
  vector<int> d(K);
  rep(i, K) cin >> d[i];

  while (q--) {
    int n, x, m;
    cin >> n >> x >> m;
    int k = K;

    if (k >= n - 1) {
      vector<int> a(n);
      a[0] = x % m;
      rep3(i, 1, n) a[i] = (a[i - 1] + d[i - 1]) % m;

      int cnt = 0;
      rep(i, n - 1) if (a[i] < a[i + 1]) cnt++;
      cout << cnt << endl;
      continue;
    }

    vector<int> d2 = d;
    rep(i, k) d2[i] %= m;

    // ">" を計算
    // a は単調増加数列だから普通 "<"
    // ">" となるのは, d2 < m に注意して, 商が 1 大きくなったとき
    ll a0 = x;
    ll an_1 = a0;

    ll sum = 0;
    rep(i, k) sum += d2[i];

    an_1 += n / k * sum;
    if (n % k == 0) {
      an_1 -= d2[n - 1];
    } else {
      rep(i, n % k - 1) { an_1 += d2[i]; }
    }

    ll ans = an_1 / m - a0 / m;
    // cout << endl << ans << endl;

    // "=" を計算
    sum = 0;
    rep(i, k) if (d2[i] == 0) sum++;
    ans += n / k * sum;
    if (n % k == 0) {
      if (d2[k - 1] == 0)
        ans--;
    } else {
      rep(i, n % k - 1) {
        if (d2[i] == 0)
          ans++;
      }
    }

    ans = n - 1 - ans; // "<" = 全体 - "=" - ">"
    cout << ans << endl;
  }
}


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 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()
const int inf = 1e9 + 7;
const ll INF = 1e18;
#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;
}
template <typename T> T gcd(T a, T b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
template <typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template <typename T> T pow(T a, int b) {
  return b ? pow(a * a, b / 2) * (b % 2 ? a : 1) : 1;
}
const int mod = 1000000007;
ll modpow(ll a, int b) {
  return b ? modpow(a * a % mod, b / 2) * (b % 2 ? a : 1) % mod : 1;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &vec) {
  for (auto &vi : vec)
    os << vi << " ";
  return os;
}
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << p.F << " " << p.S;
  return os;
}
template <class T> inline void add(T &a, int b) {
  a += b;
  if (a >= mod)
    a -= mod;
}

void solve();

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  int T;
  // cin >> T;
  T = 1;

  while (T--) {
    solve();
  }
}

void solve() {
  int K, q;
  cin >> K >> q;
  vector<int> d(K);
  rep(i, K) cin >> d[i];

  while (q--) {
    int n, x, m;
    cin >> n >> x >> m;
    int k = K;

    if (k >= n - 1) {
      vector<int> a(n);
      a[0] = x % m;
      rep3(i, 1, n) a[i] = (a[i - 1] + d[i - 1]) % m;

      int cnt = 0;
      rep(i, n - 1) if (a[i] < a[i + 1]) cnt++;
      cout << cnt << endl;
      continue;
    }

    vector<int> d2 = d;
    rep(i, k) d2[i] %= m;

    // ">" を計算
    // a は単調増加数列だから普通 "<"
    // ">" となるのは, d2 < m に注意して, 商が 1 大きくなったとき
    ll a0 = x;
    ll an_1 = a0;

    ll sum = 0;
    rep(i, k) sum += d2[i];

    an_1 += n / k * sum;
    if (n % k == 0) {
      an_1 -= d2[k - 1]; // debuged
    } else {
      rep(i, n % k - 1) { an_1 += d2[i]; }
    }

    ll ans = an_1 / m - a0 / m;
    // cout << endl << ans << endl;

    // "=" を計算
    sum = 0;
    rep(i, k) if (d2[i] == 0) sum++;
    ans += n / k * sum;
    if (n % k == 0) {
      if (d2[k - 1] == 0)
        ans--;
    } else {
      rep(i, n % k - 1) {
        if (d2[i] == 0)
          ans++;
      }
    }

    ans = n - 1 - ans; // "<" = 全体 - "=" - ">"
    cout << ans << endl;
  }
}