Problem p03790 (C++)

Buggy submission (status: Runtime Error):
#pragma comment(linker, "/STACK:1000000000")
#define _CRT_SECURE_NO_WARNINGS
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#define mp make_pair
#define pb push_back

typedef long long ll;
typedef long double ld;

using namespace std;

const int MAXN = 200001;
int a[MAXN];
int b[MAXN];
ll s[MAXN];
const ll INF = 1000ll * 1000ll * 1000ll * 1000ll * 1000ll * 100ll;

struct node {
  ll mdf;
  ll val;
  ll val2;
  node *l;
  node *r;
};

typedef node *pnode;

void setval(pnode t, int l, int r, ll vl) {
  t->mdf = t->val = vl;
  t->val2 = vl + l;
}

pnode newnode(int l, int r) {
  pnode ans = new node();
  setval(ans, l, r, 0);
  return ans;
}

void upd(pnode t) {
  t->val = min(t->l->val, t->r->val);
  t->val2 = min(t->l->val2, t->r->val2);
}

void push(pnode t, int l, int r) {
  int md = (l + r) / 2;
  if (!(t->l))
    t->l = newnode(l, md);
  if (!(t->r))
    t->r = newnode(md + 1, r);
  if (t->mdf != -1) {
    setval(t->l, l, md, t->mdf);
    setval(t->r, md + 1, r, t->mdf);
    t->mdf = -1;
  }
}

pnode root;

int n;
int k;
int lv, rv;
ll nval;

ll rmq_get(pnode t, int l, int r) {
  if ((l > rv) || (lv > r))
    return INF;
  if ((lv <= l) && (r <= rv))
    return t->val2;
  push(t, l, r);
  return min(rmq_get(t->l, l, (l + r) / 2), rmq_get(t->r, (l + r) / 2 + 1, r));
}

void rmq_modify(pnode t, int l, int r) {
  if ((l > rv) || (lv > r))
    return;
  if ((lv <= l) && (r <= rv)) {
    setval(t, l, r, nval);
    return;
  }
  push(t, l, r);
  rmq_modify(t->l, l, (l + r) / 2);
  rmq_modify(t->r, (l + r) / 2 + 1, r);
  upd(t);
}

ll g2(int md) {
  lv = 0, rv = md;
  ll ans = INF;
  ans = min(ans, rmq_get(root, 0, k - 1) + k - md);
  lv = md, rv = k - 1;
  ans = min(ans, rmq_get(root, 0, k - 1) - md);
  return ans;
}

int main() {
  ios_base::sync_with_stdio(0);
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
  cin >> n >> k;
  root = newnode(0, k - 1);
  ll sm = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    a[i] *= 2;
    sm += a[i];
  }
  ll md = 0;
  for (int i = 0; i < n; i++) {
    if ((a[i] > k) && (b[i] == 1)) {
      cout << -1 << endl;
      return 0;
    }
    if (b[i] == 1) {
      ll val = g2(md);
      int dlv = (md + 1) % k, drv = (md + a[i] - 1) % k;
      nval = INF;
      if (dlv > drv) {
        lv = 0, rv = drv;
        rmq_modify(root, 0, k - 1);
        lv = dlv, rv = k - 1;
        rmq_modify(root, 0, k - 1);
      } else {
        lv = dlv, rv = drv;
        rmq_modify(root, 0, k - 1);
      }
      nval = val;
      lv = rv = md;
      rmq_modify(root, 0, k - 1);
      md = (md + a[i]) % k;
    } else {
      md = (md + a[i]) % k;
      nval = g2(md);
      lv = rv = md;
      rmq_modify(root, 0, k - 1);
    }
  }
  if (root->val < INF)
    cout << sm + root->val << endl;
  else
    cout << -1 << endl;
  return 0;
}

Fixed submission:
#pragma comment(linker, "/STACK:1000000000")
#define _CRT_SECURE_NO_WARNINGS
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#define mp make_pair
#define pb push_back

typedef long long ll;
typedef long double ld;

using namespace std;

const int MAXN = 200001;
int a[MAXN];
int b[MAXN];
ll s[MAXN];
const ll INF = 1000ll * 1000ll * 1000ll * 1000ll * 1000ll * 100ll;

struct node {
  ll mdf;
  ll val;
  ll val2;
  node *l;
  node *r;
};

typedef node *pnode;

void setval(pnode t, int l, int r, ll vl) {
  t->mdf = t->val = vl;
  t->val2 = vl + l;
}

pnode newnode(int l, int r) {
  pnode ans = new node();
  setval(ans, l, r, 0);
  return ans;
}

void upd(pnode t) {
  t->val = min(t->l->val, t->r->val);
  t->val2 = min(t->l->val2, t->r->val2);
}

void push(pnode t, int l, int r) {
  int md = (l + r) / 2;
  if (!(t->l))
    t->l = newnode(l, md);
  if (!(t->r))
    t->r = newnode(md + 1, r);
  if (t->mdf != -1) {
    setval(t->l, l, md, t->mdf);
    setval(t->r, md + 1, r, t->mdf);
    t->mdf = -1;
  }
}

pnode root;

int n;
int k;
int lv, rv;
ll nval;

ll rmq_get(pnode t, int l, int r) {
  if ((l > rv) || (lv > r))
    return INF;
  if ((lv <= l) && (r <= rv))
    return t->val2;
  push(t, l, r);
  return min(rmq_get(t->l, l, (l + r) / 2), rmq_get(t->r, (l + r) / 2 + 1, r));
}

void rmq_modify(pnode t, int l, int r) {
  if ((l > rv) || (lv > r))
    return;
  if ((lv <= l) && (r <= rv)) {
    setval(t, l, r, nval);
    return;
  }
  push(t, l, r);
  rmq_modify(t->l, l, (l + r) / 2);
  rmq_modify(t->r, (l + r) / 2 + 1, r);
  upd(t);
}

ll g2(int md) {
  lv = 0, rv = md;
  ll ans = INF;
  ans = min(ans, rmq_get(root, 0, k - 1) + k - md);
  lv = md, rv = k - 1;
  ans = min(ans, rmq_get(root, 0, k - 1) - md);
  return ans;
}

int main() {
  ios_base::sync_with_stdio(0);
  //	freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
  cin >> n >> k;
  root = newnode(0, k - 1);
  ll sm = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    a[i] *= 2;
    sm += a[i];
  }
  ll md = 0;
  for (int i = 0; i < n; i++) {
    if ((a[i] > k) && (b[i] == 1)) {
      cout << -1 << endl;
      return 0;
    }
    if (b[i] == 1) {
      ll val = g2(md);
      int dlv = (md + 1) % k, drv = (md + a[i] - 1) % k;
      nval = INF;
      if (dlv > drv) {
        lv = 0, rv = drv;
        rmq_modify(root, 0, k - 1);
        lv = dlv, rv = k - 1;
        rmq_modify(root, 0, k - 1);
      } else {
        lv = dlv, rv = drv;
        rmq_modify(root, 0, k - 1);
      }
      nval = val;
      lv = rv = md;
      rmq_modify(root, 0, k - 1);
      md = (md + a[i]) % k;
    } else {
      md = (md + a[i]) % k;
      nval = g2(md);
      lv = rv = md;
      rmq_modify(root, 0, k - 1);
    }
  }
  if (root->val < INF)
    cout << sm + root->val << endl;
  else
    cout << -1 << endl;
  return 0;
}