Problem p02575 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;

#pragma region macros_and_aliases

#define rep(i, n) for (long long i = 0; i < (n); i++)
#define rrep(i, n) for (long long i = (n)-1; i > -1; i--)
#define Rep(i, m, n) for (long long i = (m); i < (n); i++)
#define rRep(i, m, n) for (long long i = (n)-1; i >= (m); i--)
#define REP(i, m, n, p) for (long long i = m; i < n; i += p)
#define foa(s, v) for (auto &s : v)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define bcnt(n) __builtin_popcountll(n)
#define endk endl
#define ednl endl
#define enld endl

using ll = long long;
using ld = long double;
using vb = vector<bool>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vvvi = vector<vector<vector<int>>>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using mll = map<long long, long long>;
using pll = pair<long long, long long>;
using qll = queue<long long>;
using sll = set<long long>;
using vpll = vector<pair<long long, long long>>;
template <class T = ll> using V = vector<T>;
template <class T = ll> using VV = V<V<T>>;
template <class T = ll> using VVV = V<V<V<T>>>;
// 昇順pq(小さい方から取り出す)
template <class T = ll> using pqup = priority_queue<T, vector<T>, greater<T>>;
// 降順pq(大きい方から取り出す)
template <class T = ll> using pqdn = priority_queue<T>;

#pragma region debug
#define debug(var)                                                             \\
  do {                                                                         \\
    std::cout << #var << " : ";                                                \\
    view(var);                                                                 \\
  } while (0)

template <typename T> void view(T e) { std::cout << e << "\\n"; }
template <typename T> void view(const std::vector<T> &v) {
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << "\\n";
}
template <typename T> void view(const std::set<T> &s) {
  for (auto &t : s) {
    std::cout << t << " ";
  }
  std::cout << "\\n";
}
template <typename T> void view(const std::vector<std::vector<T>> &vv) {
  std::cout << "\\n";
  for (const auto &v : vv) {
    view(v);
  }
}
template <typename T, typename U>
void view(const std::vector<std::pair<T, U>> &v) {
  std::cout << "\\n";
  for (const auto &c : v) {
    std::cout << c.first << " " << c.second << "\\n";
  }
}
template <typename T, typename U> void view(const std::map<T, U> &m) {
  std::cout << "\\n";
  for (auto &t : m) {
    std::cout << t.first << " " << t.second << "\\n";
  }
}

#pragma endregion

#pragma region input
#define VEC(type, name, size)                                                  \\
  vector<type> name(size);                                                     \\
  IN(name)
#define VVEC(type, name, h, w)                                                 \\
  vector<vector<type>> name(h, vector<type>(w));                               \\
  IN(name)
#define INT(...)                                                               \\
  int __VA_ARGS__;                                                             \\
  IN(__VA_ARGS__)
#define LL(...)                                                                \\
  long long __VA_ARGS__;                                                       \\
  IN(__VA_ARGS__)
#define STR(...)                                                               \\
  string __VA_ARGS__;                                                          \\
  IN(__VA_ARGS__)
#define CHAR(...)                                                              \\
  char __VA_ARGS__;                                                            \\
  IN(__VA_ARGS__)
#define DOUBLE(...)                                                            \\
  double __VA_ARGS__;                                                          \\
  IN(__VA_ARGS__)
#define LD(...)                                                                \\
  long double __VA_ARGS__;                                                     \\
  IN(__VA_ARGS__)

template <class T> void scan(T &a) { cin >> a; }
template <class T> void scan(vector<T> &a) {
  for (auto &i : a)
    scan(i);
}
template <class T, class L> void scan(pair<T, L> &p) {
  scan(p.first);
  scan(p.second);
}
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &...tail) {
  scan(head);
  IN(tail...);
}
template <class T> inline void print(T x) { cout << x << '\\n'; }

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
#pragma endregion

#pragma endregion

#pragma region constants

long long const limLL = 9223372036854775807; // POW(2,63)-1 ~ 9.22e18
long long const dekai = 3e16;
const long double pi = acos(-1);
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
int ddx[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};

const int mod = 1000000007;
// const int mod = 998244353;
#pragma endregion

#pragma region basic_procedure

template <class T> inline bool isin(T x, T lef, T rig) {
  return ((lef <= x) && (x < rig));
}

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;
}

void Yes(bool f = 1) { cout << (f ? "Yes" : "No") << "\\n"; }
void No() { cout << "No\\n"; }
void YES(bool f = 1) { cout << (f ? "YES" : "NO") << "\\n"; }
void NO() { cout << "NO\\n"; }
void err() {
  cout << -1 << "\\n";
  exit(0);
}

vector<long long>
vin(long long n) { // 整数n個の入力を受け取ってベクトルに突っ込んで返す
  vector<long long> v(n);
  for (long long i = 0; i < n; i++) {
    cin >> v[i];
  }
  return v;
}

// ベクトルの出力(検証済)
//  vectorの中身を出力する 答えの出力に利用可能
template <class T> void vout(vector<T> &v, bool tate = 0) {
  if (v.size() > 0) {
    for (auto it = v.begin(); it < v.end(); it++) {
      cout << *it;
      if (it != v.end() - 1) {
        if (tate)
          cout << endl;
        else
          cout << " ";
      }
    }
  }
  cout << endl;
}

template <class T> void add(vector<T> &v, T val) { // ベクトルの各要素に加算
  for (auto &a : v)
    a += val;
  return;
}

// vectorの中身を数える map<要素,個数>を返す
template <class T> map<T, long long> cntv(vector<T> v) {
  map<T, long long> m;
  for (auto &g : v) {
    if (m.count(g))
      m[g]++;
    else
      m[g] = 1;
  }
  return m;
}

// 配列圧縮(検証済)
//{1,36,1,3,8,-2,-92}を
//{2, 5,2,3,4, 1,  0}にする
template <class T> vector<long long> press(vector<T> &v) {
  long long n = v.size();
  vector<long long> w(n);
  map<T, long long> m;
  for (T &p : v)
    m[p] = 0;
  long long i = 0;
  for (auto &p : m) {
    p.second = i;
    i++;
  }
  for (long long i = 0; i < n; i++)
    w.at(i) = m[v.at(i)];
  return w;
}

template <class T> T divup(T a, T b) {
  // 端数繰りあがり割り算
  assert(b != 0);
  T x = abs(a);
  T y = abs(b);
  T z = (x + y - 1) / y;
  if ((a < 0 && b > 0) || (a > 0 && b < 0))
    return -z;
  else if (a == 0)
    return 0;
  else
    return z;
}

long long POW(long long a, long long n) {
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a;
    a = a * a;
    n >>= 1;
  }
  return res;
}

template <class T> int sgn(T x) { // 符号関数
  if (x < 0)
    return -1;
  if (x == 0)
    return 0;
  return 1;
}

long long modpow(long long a, long long n, long long mod) { // a^n mod
  if (mod == 1)
    return 0LL;
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}

// a * x % mod == __gcd(a,mod)なるxを返す
// a が modの倍数でないことが条件
long long modinv(long long a, long long mod) {
  long long b = mod, u = 1, v = 0;
  while (b) {
    long long t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  u %= mod;
  if (u < 0)
    u += mod;
  return u;
}

vvll comb(100, vll(100, -1));
long long com(long long n, long long k) { // 普通の二項計数(overflowに注意)
  assert(n < 100 && k < 100);
  if (n < k || k < 0 || n < 0)
    return 0;
  if (comb[n][k] != -1)
    return comb[n][k];
  ll res;
  if (n - k < k)
    res = com(n, n - k);
  else if (k == 0)
    res = 1;
  else
    res = com(n - 1, k - 1) + com(n - 1, k);
  comb[n][k] = res;
  return res;
}

// nCk modを求める
const ll MAX = 5100000;
// この値は求める二項計数の値に応じて変える
// MAX=3*10^7のとき1900msほど、ほぼ比例
// MAX=5*10^6程度ならそれほど気にしなくてよい(300ms程)
long long fac[MAX], finv[MAX], inv[MAX];

void cominit() {
  // テーブルを作る前処理
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (ll 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;
  }
}
long long commod(ll n, ll k) { // 二項係数計算
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % mod) % mod;
}
long long pmod(ll n, ll k) { // 順列計算
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * finv[n - k] % mod;
}
long long hmod(ll n, ll k) { // nHk計算
  // n個の区別しないoを区別するk個の箱に入れる方法の総数
  //(n+k-1)C(k-1)と等しい
  return commod(n + k - 1, n);
}
#pragma endregion

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  // cout << fixed << setprecision(15);
  int h, w;
  cin >> h >> w;
  V<pair<int, int>> a(h);
  rep(i, h) cin >> a[i], a[i].first--;

  using p = pair<int, int>;
  set<p> se;
  multiset<int> ms;

  rep(i, w) { se.insert({i, 0}); } // place , moved
  rep(i, w) ms.insert(0);

  V<int> ans(h, -1);
  rep(i, h) {
    // debug(se);
    // foa(t, ms) { cout << t << endl; }
    int mini = 1e8;
    int lef, rig;
    tie(lef, rig) = a[i];
    auto it = se.lower_bound({lef, -1});

    while (it != se.end() && (*it).first < rig) {
      int pla = (*it).first;
      int moved = (*it).second;
      chmin(mini, rig - pla + moved);

      // debug(pla);
      // debug(moved);
      // debug(mini);

      auto it2 = ms.find(moved);
      if (it2 != ms.end())
        ms.erase(it2);

      it = se.erase(it);
    }
    if (rig != w && mini != 1e8) {
      ms.insert(mini);
      se.insert({rig, mini});
      // debug(mini);
    }

    if (ms.empty())
      ans[i] = -1;
    else
      ans[i] = *(ms.begin()) + i + 1;
  }
  vout(ans, 1);
}


Error: -11

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

#pragma region macros_and_aliases

#define rep(i, n) for (long long i = 0; i < (n); i++)
#define rrep(i, n) for (long long i = (n)-1; i > -1; i--)
#define Rep(i, m, n) for (long long i = (m); i < (n); i++)
#define rRep(i, m, n) for (long long i = (n)-1; i >= (m); i--)
#define REP(i, m, n, p) for (long long i = m; i < n; i += p)
#define foa(s, v) for (auto &s : v)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define bcnt(n) __builtin_popcountll(n)
#define endk endl
#define ednl endl
#define enld endl

using ll = long long;
using ld = long double;
using vb = vector<bool>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vvvi = vector<vector<vector<int>>>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using mll = map<long long, long long>;
using pll = pair<long long, long long>;
using qll = queue<long long>;
using sll = set<long long>;
using vpll = vector<pair<long long, long long>>;
template <class T = ll> using V = vector<T>;
template <class T = ll> using VV = V<V<T>>;
template <class T = ll> using VVV = V<V<V<T>>>;
// 昇順pq(小さい方から取り出す)
template <class T = ll> using pqup = priority_queue<T, vector<T>, greater<T>>;
// 降順pq(大きい方から取り出す)
template <class T = ll> using pqdn = priority_queue<T>;

#pragma region debug
#define debug(var)                                                             \\
  do {                                                                         \\
    std::cout << #var << " : ";                                                \\
    view(var);                                                                 \\
  } while (0)

template <typename T> void view(T e) { std::cout << e << "\\n"; }
template <typename T> void view(const std::vector<T> &v) {
  for (const auto &e : v) {
    std::cout << e << " ";
  }
  std::cout << "\\n";
}
template <typename T> void view(const std::set<T> &s) {
  for (auto &t : s) {
    std::cout << t << " ";
  }
  std::cout << "\\n";
}
template <typename T> void view(const std::vector<std::vector<T>> &vv) {
  std::cout << "\\n";
  for (const auto &v : vv) {
    view(v);
  }
}
template <typename T, typename U>
void view(const std::vector<std::pair<T, U>> &v) {
  std::cout << "\\n";
  for (const auto &c : v) {
    std::cout << c.first << " " << c.second << "\\n";
  }
}
template <typename T, typename U> void view(const std::map<T, U> &m) {
  std::cout << "\\n";
  for (auto &t : m) {
    std::cout << t.first << " " << t.second << "\\n";
  }
}

#pragma endregion

#pragma region input
#define VEC(type, name, size)                                                  \\
  vector<type> name(size);                                                     \\
  IN(name)
#define VVEC(type, name, h, w)                                                 \\
  vector<vector<type>> name(h, vector<type>(w));                               \\
  IN(name)
#define INT(...)                                                               \\
  int __VA_ARGS__;                                                             \\
  IN(__VA_ARGS__)
#define LL(...)                                                                \\
  long long __VA_ARGS__;                                                       \\
  IN(__VA_ARGS__)
#define STR(...)                                                               \\
  string __VA_ARGS__;                                                          \\
  IN(__VA_ARGS__)
#define CHAR(...)                                                              \\
  char __VA_ARGS__;                                                            \\
  IN(__VA_ARGS__)
#define DOUBLE(...)                                                            \\
  double __VA_ARGS__;                                                          \\
  IN(__VA_ARGS__)
#define LD(...)                                                                \\
  long double __VA_ARGS__;                                                     \\
  IN(__VA_ARGS__)

template <class T> void scan(T &a) { cin >> a; }
template <class T> void scan(vector<T> &a) {
  for (auto &i : a)
    scan(i);
}
template <class T, class L> void scan(pair<T, L> &p) {
  scan(p.first);
  scan(p.second);
}
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &...tail) {
  scan(head);
  IN(tail...);
}
template <class T> inline void print(T x) { cout << x << '\\n'; }

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
#pragma endregion

#pragma endregion

#pragma region constants

long long const limLL = 9223372036854775807; // POW(2,63)-1 ~ 9.22e18
long long const dekai = 3e16;
const long double pi = acos(-1);
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
int ddx[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};

const int mod = 1000000007;
// const int mod = 998244353;
#pragma endregion

#pragma region basic_procedure

template <class T> inline bool isin(T x, T lef, T rig) {
  return ((lef <= x) && (x < rig));
}

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;
}

void Yes(bool f = 1) { cout << (f ? "Yes" : "No") << "\\n"; }
void No() { cout << "No\\n"; }
void YES(bool f = 1) { cout << (f ? "YES" : "NO") << "\\n"; }
void NO() { cout << "NO\\n"; }
void err() {
  cout << -1 << "\\n";
  exit(0);
}

vector<long long>
vin(long long n) { // 整数n個の入力を受け取ってベクトルに突っ込んで返す
  vector<long long> v(n);
  for (long long i = 0; i < n; i++) {
    cin >> v[i];
  }
  return v;
}

// ベクトルの出力(検証済)
//  vectorの中身を出力する 答えの出力に利用可能
template <class T> void vout(vector<T> &v, bool tate = 0) {
  if (v.size() > 0) {
    for (auto it = v.begin(); it < v.end(); it++) {
      cout << *it;
      if (it != v.end() - 1) {
        if (tate)
          cout << endl;
        else
          cout << " ";
      }
    }
  }
  cout << endl;
}

template <class T> void add(vector<T> &v, T val) { // ベクトルの各要素に加算
  for (auto &a : v)
    a += val;
  return;
}

// vectorの中身を数える map<要素,個数>を返す
template <class T> map<T, long long> cntv(vector<T> v) {
  map<T, long long> m;
  for (auto &g : v) {
    if (m.count(g))
      m[g]++;
    else
      m[g] = 1;
  }
  return m;
}

// 配列圧縮(検証済)
//{1,36,1,3,8,-2,-92}を
//{2, 5,2,3,4, 1,  0}にする
template <class T> vector<long long> press(vector<T> &v) {
  long long n = v.size();
  vector<long long> w(n);
  map<T, long long> m;
  for (T &p : v)
    m[p] = 0;
  long long i = 0;
  for (auto &p : m) {
    p.second = i;
    i++;
  }
  for (long long i = 0; i < n; i++)
    w.at(i) = m[v.at(i)];
  return w;
}

template <class T> T divup(T a, T b) {
  // 端数繰りあがり割り算
  assert(b != 0);
  T x = abs(a);
  T y = abs(b);
  T z = (x + y - 1) / y;
  if ((a < 0 && b > 0) || (a > 0 && b < 0))
    return -z;
  else if (a == 0)
    return 0;
  else
    return z;
}

long long POW(long long a, long long n) {
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a;
    a = a * a;
    n >>= 1;
  }
  return res;
}

template <class T> int sgn(T x) { // 符号関数
  if (x < 0)
    return -1;
  if (x == 0)
    return 0;
  return 1;
}

long long modpow(long long a, long long n, long long mod) { // a^n mod
  if (mod == 1)
    return 0LL;
  long long res = 1;
  while (n > 0) {
    if (n & 1)
      res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}

// a * x % mod == __gcd(a,mod)なるxを返す
// a が modの倍数でないことが条件
long long modinv(long long a, long long mod) {
  long long b = mod, u = 1, v = 0;
  while (b) {
    long long t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  u %= mod;
  if (u < 0)
    u += mod;
  return u;
}

vvll comb(100, vll(100, -1));
long long com(long long n, long long k) { // 普通の二項計数(overflowに注意)
  assert(n < 100 && k < 100);
  if (n < k || k < 0 || n < 0)
    return 0;
  if (comb[n][k] != -1)
    return comb[n][k];
  ll res;
  if (n - k < k)
    res = com(n, n - k);
  else if (k == 0)
    res = 1;
  else
    res = com(n - 1, k - 1) + com(n - 1, k);
  comb[n][k] = res;
  return res;
}

// nCk modを求める
const ll MAX = 5100000;
// この値は求める二項計数の値に応じて変える
// MAX=3*10^7のとき1900msほど、ほぼ比例
// MAX=5*10^6程度ならそれほど気にしなくてよい(300ms程)
long long fac[MAX], finv[MAX], inv[MAX];

void cominit() {
  // テーブルを作る前処理
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (ll 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;
  }
}
long long commod(ll n, ll k) { // 二項係数計算
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * (finv[k] * finv[n - k] % mod) % mod;
}
long long pmod(ll n, ll k) { // 順列計算
  if (n < k)
    return 0;
  if (n < 0 || k < 0)
    return 0;
  return fac[n] * finv[n - k] % mod;
}
long long hmod(ll n, ll k) { // nHk計算
  // n個の区別しないoを区別するk個の箱に入れる方法の総数
  //(n+k-1)C(k-1)と等しい
  return commod(n + k - 1, n);
}
#pragma endregion

template <class T = long long, class U = long long> class LazyST {
  // private:
public:
  int n;
  int height = -1;     // 木の高さ
  vector<T> data;      // monoid
  vector<U> lazy;      // operator
  T unit_data;         // monoid単位元
  U unit_lazy;         // operator単位元
  function<T(T, T)> f; // monoid同士の演算
  function<T(T, U)> g; // monoidとoperatorとの演算
  function<U(U, U)> h; // operator同士の演算
  void propagate(int lef, int rig) {
    // 遅延させていた作用素を上から伝播させる [lef,rig)に有効な範囲で
    lef += n;
    rig += n - 1; // 閉区間にする
    for (int i = height; i > 0; i--) {
      int l = lef >> i;
      int r = rig >> i;
      lazy[l << 1] = h(lazy[l << 1], lazy[l]);
      lazy[l << 1 | 1] = h(lazy[l << 1 | 1], lazy[l]);
      data[l] = g(data[l], lazy[l]);
      lazy[l] = unit_lazy;
      lazy[r << 1] = h(lazy[r << 1], lazy[r]);
      lazy[r << 1 | 1] = h(lazy[r << 1 | 1], lazy[r]);
      data[r] = g(data[r], lazy[r]);
      lazy[r] = unit_lazy;
    }
  }

  // 全て同じmonoid = init_dataで初期化
  LazyST(int _n, function<T(T, T)> ope_data_data,
         function<T(T, U)> ope_data_lazy, function<U(U, U)> ope_lazy_lazy,
         T _unit_data, U _unit_lazy, T init_data)
      : n(_n), f(ope_data_data), g(ope_data_lazy), h(ope_lazy_lazy),
        unit_data(_unit_data), unit_lazy(_unit_lazy) {
    data.assign(n * 2, unit_data);
    for (int i = 0; i < n; i++) {
      data[i + n] = init_data;
    }
    for (int i = n - 1; i > -1; i--) {
      data[i] = f(data[i << 1], data[i << 1 | 1]);
    }
    lazy.assign(n * 2, unit_lazy);
    for (int i = 1; i <= n; i *= 2)
      height++;
  }
  // 初期化配列をvectorで渡す
  LazyST(int _n, function<T(T, T)> ope_data_data,
         function<T(T, U)> ope_data_lazy, function<U(U, U)> ope_lazy_lazy,
         T _unit_data, U _unit_lazy, vector<T> raw_data)
      : n(_n), f(ope_data_data), g(ope_data_lazy), h(ope_lazy_lazy),
        unit_data(_unit_data), unit_lazy(_unit_lazy) {
    data.assign(n * 2, unit_data);
    for (int i = 0; i < n; i++) {
      data[i + n] = raw_data[i];
    }
    for (int i = n - 1; i > -1; i--) {
      data[i] = f(data[i << 1], data[i << 1 | 1]);
    }
    lazy.assign(n * 2, unit_lazy);
    for (int i = 1; i <= n; i *= 2)
      height++;
  }

  void update(int lef, int rig, U _operator) { //[lef,rig)にopeを作用させる
    propagate(lef, rig);
    lef += n;
    rig += n; // 半開区間にする 下から上にdataを更新
    int L0 = lef / (lef & -lef);
    int R0 = rig / (rig & -rig);
    while (lef < rig) {
      if (lef & 1) {
        lazy[lef] = h(lazy[lef], _operator);
        lef++;
      }
      if (rig & 1) {
        lazy[rig - 1] = h(lazy[rig - 1], _operator);
        rig--;
      }
      lef >>= 1;
      rig >>= 1;
    }
    lef = L0;
    rig = R0;
    while (lef > 1) {
      lef >>= 1;
      data[lef] = f(g(data[lef << 1], lazy[lef << 1]),
                    g(data[lef << 1 | 1], lazy[lef << 1 | 1]));
      lazy[lef] = unit_lazy;
    }
    while (rig > 1) {
      rig >>= 1;
      data[rig] = f(g(data[rig << 1], lazy[rig << 1]),
                    g(data[rig << 1 | 1], lazy[rig << 1 | 1]));
      lazy[rig] = unit_lazy;
    }
  }

  T get(int lef, int rig) { // 区間の値取得
    propagate(lef, rig);
    T a = unit_data, b = unit_data;
    lef += n;
    rig += n;
    while (lef < rig) {
      if (lef & 1)
        a = f(a, g(data[lef], lazy[lef]));
      if (rig & 1)
        b = f(g(data[rig - 1], lazy[rig - 1]), b);
      (lef += 1) >>= 1;
      rig >>= 1;
    }
    return f(a, b);
  }
};

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  // cout << fixed << setprecision(15);
  ll unit_upd = -dekai; // upd,PairUpdの単位元 被らなければ何でも

  // 単位元 = dekai
  auto mini = [](ll a, ll b) { return min(a, b); };
  // 単位元 = -dekai
  auto maxi = [](ll a, ll b) { return max(a, b); };
  // 単位元 = unit_upd
  auto upd = [&](ll a, ll b) { return b == unit_upd ? a : b; };

  ll lim = 1e13;
  int h, w;
  cin >> h >> w;
  vll v(w);
  rep(i, w) v[i] = i;
  LazyST<ll> lst(w, maxi, upd, upd, -dekai, unit_upd, v);
  LazyST<ll> yokomove(w, mini, upd, upd, dekai, unit_upd, 0);
  vll ans(h);

  rep(i, w) {
    int a, b;
    cin >> a >> b;
    a--;

    ll premax = lst.get(a, b);
    lst.update(a, b, -lim);

    yokomove.update(a, b, lim);
    if (b < w) {
      ll maximum = lst.get(b, b + 1);
      chmax(maximum, premax);
      lst.update(b, b + 1, maximum);
      yokomove.update(b, b + 1, b - maximum);
    }
    ans[i] = yokomove.get(0, w) + i + 1;
    if (ans[i] >= w + h + 2)
      ans[i] = -1;

    // rep(i, w) { cout << lst.get(i, i + 1) << " " << yokomove.get(i, i + 1) <<
    // endl; }
  }
  rep(i, h) cout << ans[i] << endl;
}