Submission #386475

#	Time	Username	Problem	Language	Result	Execution time	Memory
386475		VROOM_VARUN	Event Hopping 2 (JOI21_event2)	C++14	100 / 100	633 ms	43968 KiB

event2

/*
ID: varunra2
LANG: C++
TASK: hopping2
*/

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

#ifdef DEBUG
#include "lib/debug.h"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define debug_arr(...) \
  cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__)
#pragma GCC diagnostic ignored "-Wsign-compare"
//#pragma GCC diagnostic ignored "-Wunused-parameter"
//#pragma GCC diagnostic ignored "-Wunused-variable"
#else
#define debug(...) 42
#endif

#define EPS 1e-9
#define IN(A, B, C) assert(B <= A && A <= C)
#define INF (int)1e9
#define MEM(a, b) memset(a, (b), sizeof(a))
#define MOD 1000000007
#define MP make_pair
#define PB push_back
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define x first
#define y second

const double PI = acos(-1.0);
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef map<int, int> MPII;
typedef multiset<int> MSETI;
typedef set<int> SETI;
typedef set<string> SETS;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<string> VS;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto& a : x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#pragma GCC diagnostic ignored "-Wsign-compare"
// util functions

int n, k;

VII vals;

struct fenwick {
  int n;
  VI bit;
  void init(int _n) {
    n = _n;
    bit.assign(n + 1, 0);
  }

  void upd(int ind, int val) {
    while (ind <= n) {
      bit[ind] += val;
      ind += (ind & (-ind));
    }
  }

  int qry(int ind) {
    int ret = 0;
    while (ind >= 1) {
      ret += bit[ind];
      ind -= (ind & (-ind));
    }
    return ret;
  }

  int qry(int l, int r) { return qry(r) - qry(l - 1); }
};

MPII compress(VI pnts) {
  sort(all(pnts));
  pnts.erase(unique(all(pnts)), pnts.end());
  int cnt = 0;
  MPII ret;
  for (int i = 0; i < sz(pnts); i++) {
    ret[pnts[i]] = cnt++;
  }
  return ret;
}

MPII ans;
MPII cmp;
VVI lft;
const int bits = 20;

void init() {
  vals.resize(n);
  lft.resize(n);
  trav(x, lft) x.resize(bits);
}

bool ok(int ind, int r) {
  if (ind == -1) return false;
  return vals[ind].y <= r;
}

int calc(int l, int r) {
  // calculate answer for this range
  int start = ans[l];
  if (!ok(start, r)) return 0;
  int ret = 0;
  for (int i = bits - 1; i >= 0; i--) {
    if (ok(lft[start][i], r)) {
      start = lft[start][i];
      ret += (1 << i);
    }
  }
  return ret + 1;
}

int main() {
// #ifndef ONLINE_JUDGE
  // freopen("hopping2.in", "r", stdin);
  // freopen("hopping2.out", "w", stdout);
// #endif
  cin.sync_with_stdio(0);
  cin.tie(0);

  cin >> n >> k;

  init();

  trav(x, vals) cin >> x.x >> x.y;

  VI pnts;

  trav(x, vals) pnts.PB(x.x), pnts.PB(x.y);

  cmp = compress(pnts);

  trav(x, vals) x.x = cmp[x.x], x.y = cmp[x.y];

  PII bst(INF, -1);

  VVI evnts;

  rep(i, 0, n) {
    evnts.PB({vals[i].x, 1, i});
    evnts.PB({vals[i].y, 0, i});
  }

  sort(all(evnts), greater<VI>());

  for (auto& x : evnts) {
    if (x[1] == 1) {
      bst = min(bst, MP(vals[x[2]].y, x[2]));
    } else {
      ans[vals[x[2]].y] = bst.y;
    }
  }

  ans[0] = bst.y;

  for (int i = 0; i < n; i++) {
    lft[i][0] = ans[vals[i].y];
  }

  for (int j = 1; j < bits; j++) {
    for (int i = 0; i < n; i++) {
      int to = lft[i][j - 1];
      if (to == -1)
        lft[i][j] = -1;
      else
        lft[i][j] = lft[to][j - 1];
    }
  }

  VI ret;
  int cnt = 0;

  set<PII> gps;

  gps.insert(MP(0, 2 * n));

  int gpcnt = calc(0, 2 * n);

  for (int i = 0; i < n; i++) {
    // debug(i);
    if (cnt == k) break;
    int l = vals[i].x;
    int r = vals[i].y;
    auto it = gps.upper_bound(MP(l, INF));
    if (it == gps.begin()) continue;
    it--;
    auto x = *it;
    // debug(gps);
    int rl = x.x;
    int rr = x.y;
    if (!(l >= rl and r <= rr)) continue;
    // rl, rr -> (rl, l), (r, rr)
    // calculate contribution of rl, rr (a)
    // calculate contribution of rl, l (b)
    // calculate contribution of r, rr (c)
    // this is a good range, add this mf
    int a = calc(rl, rr);
    int b = calc(rl, l);
    int c = calc(r, rr);
    // debug(a, b, c, cnt, gpcnt);
    // debug(l, r);
    // debug(rl, rr);
    // debug(cnt + gpcnt - a + b + c + 1);
    if (cnt + gpcnt - a + b + c + 1 >= k) {
      ret.PB(i + 1);
      cnt++;
      gpcnt -= a;
      gpcnt += (b + c);
      gps.erase(it);
      PII pl(rl, l);
      PII pr(r, rr);
      if (pl.x != pl.y) {
        gps.insert(pl);
      }
      if (pr.x != pr.y) {
        gps.insert(pr);
      }
    }
  }

  // debug(ret);

  if (sz(ret) != k) {
    cout << "-1\n";
    return 0;
  }

  trav(x, ret) cout << x << '\n';

  return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 1 / 1
• Subtask 3: 31 / 31
• Subtask 4: 61 / 61