oj.uz

Submission #593449

# Submission time Handle Problem Language Result Execution time Memory
593449 2022-07-11T08:00:31 Z slime Event Hopping (BOI22_events) C++14
30 / 100
 481 ms 83592 KB 
#include "bits/stdc++.h"
using namespace std;
#define int long long
#ifdef ONLINE_JUDGE
const int MAXN = 3e5 + 10;
#endif
#ifndef ONLINE_JUDGE
const int MAXN = 1029;
#endif
const int MOD = 1e9 + 7;
#define ll __int128
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
  int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
ll read() { int x; cin >> x; return (ll)x; }
long long bm(long long b, long long p) {
  if(p==0) return 1 % MOD;
  long long r = bm(b, p >> 1);
  if(p&1) return (((r*r) % MOD) * b) % MOD;
  return (r*r) % MOD;
}
long long inv(long long b) { 
  return bm(b, MOD-2);
}
long long f[MAXN];
long long nCr(int n, int r) { 
  long long ans = f[n]; ans *= inv(f[r]); ans %= MOD;
  ans *= inv(f[n-r]); ans %= MOD; return ans;
}
long long fib[MAXN], lucas[MAXN];
void precomp() { 
  for(int i=0; i<MAXN; i++) f[i] = (i == 0 ? 1 % MOD : (f[i-1] * i) % MOD); 
  lucas[0] = 2;
  lucas[1] = 1;
  for(int i=2; i<MAXN; i++) lucas[i] = (lucas[i-2] + lucas[i-1]) % MOD;
  fib[0] = 0;
  fib[1] = 1;
  for(int i=2; i<MAXN; i++) fib[i] = (fib[i-2] + fib[i-1]) % MOD;
}
int fastlog(int x) {
  return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void gay(int i) { cout << "Case #" << i << ": "; }
int csb(int l, int r, int k) { // count number of [l, r] such that i & 2^k > 0
  if(l > r) return 0;
  if(l == 0) {
    int s = r / (1ll << (k+1)); // number of complete cycles
    int t = r % (1ll << (k+1));
    int ans = s * (1ll << k);
    ans += (t >= (1ll << k) ? t - (1ll << k) + 1 : 0);
    return ans;
  }
  else return csb(0, r, k) - csb(0, l - 1, k);
}
int lis(vector<int> a) {
  int n = a.size();
  int bucket[n+1];
  for(int i=1; i<=n; i++) bucket[i] = 1e18;
  int ans = 1;
  for(int x: a) {
    auto it = lower_bound(bucket + 1, bucket +n +1, x);
    int d = distance(bucket, it);
    ans = max(ans, d);
    bucket[d] = min(bucket[d], x);
  }
  return ans;
}
struct event {
  int s, e;
  int id;
};
bool cmp_s(event x, event y) {
  return x.s < y.s;
}
bool cmp_e(event x, event y) {
  return x.e < y.e;
}
struct segtree_basic {
  struct node {
    int lazyval, mi, ma, sum; char lazytag;
    int len; // not changing
  };
  int stok;
  vector<node> st;
  void bu(int l, int r, int idx) {
    st[idx].lazyval = st[idx].mi = st[idx].ma = st[idx].sum = 0;
    st[idx].lazytag = '?';
    st[idx].len = r - l + 1;
    if(l == r) {
      return;
    }
    int mid = (l + r) >> 1;
    bu(l, mid, 2*idx+1);
    bu(mid+1, r, 2*idx+2);
  }
  void push_down(int idx) {
    if(st[idx].lazytag == '?') return;
    if(st[idx].lazytag == ':') {
      st[2*idx+1].lazyval = st[idx].lazyval;
      st[2*idx+1].mi = st[idx].lazyval;
      st[2*idx+1].ma = st[idx].lazyval;
      st[2*idx+1].sum = st[idx].lazyval * st[2*idx+1].len;
      st[2*idx+1].lazytag = ':';
 
      st[2*idx+2].lazyval = st[idx].lazyval;
      st[2*idx+2].mi = st[idx].lazyval;
      st[2*idx+2].ma = st[idx].lazyval;
      st[2*idx+2].sum = st[idx].lazyval * st[2*idx+2].len;
      st[2*idx+2].lazytag = ':';
 
    }
    else {
      st[2*idx+1].lazyval += st[idx].lazyval;
      st[2*idx+1].mi += st[idx].lazyval;
      st[2*idx+1].ma += st[idx].lazyval;
      st[2*idx+1].sum += st[idx].lazyval * st[2*idx+1].len;
      st[2*idx+1].lazytag = (st[2*idx+1].lazytag == ':' ? ':' : '+');
 
      st[2*idx+2].lazyval += st[idx].lazyval;
      st[2*idx+2].mi += st[idx].lazyval;
      st[2*idx+2].ma += st[idx].lazyval;
      st[2*idx+2].sum += st[idx].lazyval * st[2*idx+2].len;
      st[2*idx+2].lazytag = (st[2*idx+2].lazytag == ':' ? ':' : '+');
    }
    st[idx].lazytag = '?';
    st[idx].lazyval = 0;
  }
  void push_up(int idx) {
    st[idx].mi = min(st[2*idx+1].mi, st[2*idx+2].mi);
    st[idx].ma = max(st[2*idx+1].ma, st[2*idx+2].ma);
    st[idx].sum = st[2*idx+1].sum + st[2*idx+2].sum;
  }
  void u1(int l, int r, int constl, int constr, int idx, int val) { // range := v
    if(l <= constl && constr <= r) {
      st[idx].lazyval = val;
      st[idx].mi = val;
      st[idx].ma = val;
      st[idx].sum = val * st[idx].len;
      st[idx].lazytag = ':';
      return;
    }
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) u1(l, r, mid+1, constr, 2*idx+2, val);
    else if(constr < l || r < mid + 1) u1(l, r, constl, mid, 2*idx+1, val);
    else {
      u1(l, r, constl, mid, 2*idx+1, val);
      u1(l, r, mid+1, constr, 2*idx+2, val);
    }
    push_up(idx);
  }
 
  void u2(int l, int r, int constl, int constr, int idx, int val) { // range += v
    if(l <= constl && constr <= r) {
      st[idx].lazyval += val;
      st[idx].mi += val;
      st[idx].ma += val;
      st[idx].sum += val * st[idx].len;
      st[idx].lazytag = (st[idx].lazytag == ':' ? ':' : '+');
      return;
    }
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) u2(l, r, mid+1, constr, 2*idx+2, val);
    else if(constr < l || r < mid + 1) u2(l, r, constl, mid, 2*idx+1, val);
    else {
      u2(l, r, constl, mid, 2*idx+1, val);
      u2(l, r, mid+1, constr, 2*idx+2, val);
    }
    push_up(idx);
  }
 
  int qu1(int l, int r, int constl, int constr, int idx) { // range min
    if(l <= constl && constr <= r) return st[idx].mi;
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) return qu1(l, r, mid+1, constr, 2*idx+2);
    else if(constr < l || r < mid + 1) return qu1(l, r, constl, mid, 2*idx+1);
    else {
      return min(qu1(l, r, constl, mid, 2*idx+1), qu1(l, r, mid+1, constr, 2*idx+2));
    }
  }
 
  int qu2(int l, int r, int constl, int constr, int idx) { // range max
    if(l <= constl && constr <= r) return st[idx].ma;
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) return qu2(l, r, mid+1, constr, 2*idx+2); 
    else if(constr < l || r < mid + 1) return qu2(l, r, constl, mid, 2*idx+1);
    else {
      return max(qu2(l, r, constl, mid, 2*idx+1), qu2(l, r, mid+1, constr, 2*idx+2));
    }
  }
  int qu3(int l, int r, int constl, int constr, int idx) { // range sum
    if(l <= constl && constr <= r) return st[idx].sum;
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) return qu3(l, r, mid+1, constr, 2*idx+2);
    else if(constr < l || r < mid + 1) return qu3(l, r, constl, mid, 2*idx+1);
    else {
      return qu3(l, r, constl, mid, 2*idx+1) + qu3(l, r, mid+1, constr, 2*idx+2);
    }
  }
  int qu4(int l, int r, int constl, int constr, int idx, int val) { // first at least v
    if(l <= constl && constr <= r) {
      if(st[idx].ma < val) return -1;
      while(constl < constr) {
        int mid = (constl + constr) >> 1;
        push_down(idx);
        if(st[2*idx+1].ma >= val) constr = mid, idx = 2*idx + 1;
        else constl = mid+1, idx = 2*idx + 2;
      }
      return constl;
    }
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) return qu4(l, r, mid+1, constr, 2*idx+2, val);
    else if(constr < l || r < mid + 1) return qu4(l, r, constl, mid, 2*idx+1, val);
    else {
      int lchild = qu4(l, r, constl, mid, 2*idx+1, val);
      if(lchild != -1) return lchild;
      return qu4(l, r, mid+1, constr, 2*idx+2, val);
    }
  }
  int qu5(int l, int r, int constl, int constr, int idx, int val) { // first at most v
    if(l <= constl && constr <= r) {
      if(st[idx].mi > val) return -1;
      while(constl < constr) {
        int mid = (constl + constr) >> 1;
        push_down(idx);
        if(st[2*idx+1].mi <= val) constr = mid, idx = 2*idx + 1;
        else constl = mid+1, idx = 2*idx + 2;
      }
      return constl;
    }
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) return qu5(l, r, mid+1, constr, 2*idx+2, val);
    else if(constr < l || r < mid + 1) return qu5(l, r, constl, mid, 2*idx+1, val);
    else {
      int lchild = qu5(l, r, constl, mid, 2*idx+1, val);
      if(lchild != -1) return lchild;
      return qu5(l, r, mid+1, constr, 2*idx+2, val);
    }
  }
  int qu6(int l, int r, int constl, int constr, int idx, int val) { // last at least v
    if(l <= constl && constr <= r) {
      if(st[idx].ma < val) return -1;
      while(constl < constr) {
        int mid = (constl + constr) >> 1;
        push_down(idx);
        if(st[2*idx+2].ma >= val) constl = mid+1, idx = 2*idx + 2;
        else constr = mid, idx = 2*idx + 1;
      }
      return constl;
    }
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) return qu6(l, r, mid+1, constr, 2*idx+2, val);
    else if(constr < l || r < mid + 1) return qu6(l, r, constl, mid, 2*idx+1, val);
    else {
      int rchild = qu6(l, r, mid+1, constr, 2*idx+2, val);
      if(rchild != -1) return rchild;
      return qu6(l, r, constl, mid, 2*idx+1, val);
    }
  }
  int qu7(int l, int r, int constl, int constr, int idx, int val) { // last at most v
    if(l <= constl && constr <= r) {
      if(st[idx].mi > val) return -1;
      while(constl < constr) {
        int mid = (constl + constr) >> 1;
        push_down(idx);
        if(st[2*idx+2].mi <= val) constl = mid+1, idx = 2*idx + 2;
        else constr = mid, idx = 2*idx + 1;
      }
      return constl;
    }
    int mid = (constl + constr) >> 1;
    push_down(idx);
    if(mid < l || r < constl) return qu7(l, r, mid+1, constr, 2*idx+2, val);
    else if(constr < l || r < mid + 1) return qu7(l, r, constl, mid, 2*idx+1, val);
    else {
      int rchild = qu7(l, r, mid+1, constr, 2*idx+2, val);
      if(rchild != -1) return rchild;
      return qu7(l, r, constl, mid, 2*idx+1, val);
    }
  }
  public:
  void resize(int k) {
    st.resize(4*k + 10);
    stok = k;
    bu(0, k, 0);
  }
  void range_assign(int l, int r, int v) { u1(l, r, 0, stok, 0, v); }
 
  void range_add(int l, int r, int v) { u2(l, r, 0, stok, 0, v); }
 
  int query_min(int l, int r) { return qu1(l, r, 0, stok, 0); }
 
  int query_max(int l, int r) { return qu2(l, r, 0, stok, 0); }
 
  int query_sum(int l, int r) { return qu3(l, r, 0, stok, 0); }
 
  int query_firstAtLeast(int l, int r, int v) { return qu4(l, r, 0, stok, 0, v); }
 
  int query_firstAtMost(int l, int r, int v) { return qu5(l, r, 0, stok, 0, v); }
 
  int query_lastAtLeast(int l, int r, int v) { return qu6(l, r, 0, stok, 0, v); } 
 
  int query_lastAtMost(int l, int r, int v) { return qu7(l, r, 0, stok, 0, v); }
};
bool normal_order(event x, event y) {
  return x.id < y.id;
}
void solve(int tc) {
  int n, q;
  cin >> n >> q;
  event a[n+1], b[n+1];
  set<int> discrete;
  for(int i=1; i<=n; i++) {
    cin >> a[i].s >> a[i].e;
    discrete.insert(a[i].s);
    discrete.insert(a[i].e);
    a[i].id = i;
    b[i].s = a[i].s;
    b[i].e = a[i].e;
    b[i].id = a[i].id;
  }
  int owo = 0;
  map<int, int > is;
  for(int x: discrete) {
    owo++;
    is[x] = owo;
  }
  for(int i=1; i<=n; i++) {
    a[i].s = is[a[i].s];
    b[i].s = is[b[i].s];
    a[i].e = is[a[i].e];
    b[i].e = is[b[i].e];
  }
  int opt[n+1];
  for(int i=1; i<=n; i++) opt[i] = -1;
  sort(a+1, a+n+1, cmp_s);
  sort(b+1, b+n+1, cmp_e);
  int j = 0;
  segtree_basic stb;
  stb.resize(2*n);
  for(int i=1; i<=n; i++) {
    while(j+1 <= n && a[j+1].s <= b[i].e) {
      j++;
      stb.range_assign(a[j].e, a[j].e, a[j].id);
    }
    int idx = stb.query_lastAtLeast(b[i].e, 2*n, 1);
    if(idx != -1) {
      idx = stb.query_min(idx, idx);
      opt[b[i].id] = idx;
    }
  }
  for(int i=1; i<=n; i++) if(opt[i] != -1 && b[opt[i]].e == b[i].e) opt[i] = -1;
  int st[17][n+1];
  for(int i=1; i<=n; i++) st[0][i] = opt[i];
  for(int i=1; i<17; i++) {
    for(int j=1; j<=n; j++) {
      if(st[i-1][j] != -1) st[i][j] = st[i-1][st[i-1][j]];
      else st[i][j] = -1;
    }
  }
  sort(b+1, b+n+1, normal_order);
  int mi[2*n + 1]; // for all events that end at i, min strat time
  for(int i=1; i<=2*n; i++) mi[i] = 1e9;
  for(int i=1; i<=n; i++) mi[b[i].e] = min(mi[b[i].e], b[i].s);
  while(q--) {
    int fi, se;
    cin >> fi >> se;
    if(fi == se) {
      cout << "0\n"; continue;
    }
    int ans = 0;
    for(int j=16; j>=0; j--) {
      if(st[j][fi] != -1 && b[st[j][fi]].e < b[se].e) {
        fi = st[j][fi];
        ans += (1<<j);
      }
    }
    if(b[se].s <= b[fi].e && b[fi].e <= b[se].e) cout << ans + 1 << "\n";
    else if(mi[b[se].e] <= b[fi].e && b[fi].e <= b[se].e) cout << ans + 2 << "\n";
    else cout << "impossible\n";
  }



}
int32_t main() {
  precomp();
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; //cin >> t;
  for(int i=1; i<=t; i++) solve(i);
}
// I don't know geometry.
// Teaming is unfair.

/*
6 1

4 7
11 12
7 8
2 7
10 12
6 10


5 3
*/

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 292 ms 72076 KB Output is correct
3 Correct 324 ms 72112 KB Output is correct
4 Correct 365 ms 72064 KB Output is correct
5 Correct 342 ms 73232 KB Output is correct
6 Correct 320 ms 74304 KB Output is correct
7 Correct 338 ms 74576 KB Output is correct
8 Correct 363 ms 83532 KB Output is correct
9 Correct 388 ms 83348 KB Output is correct
10 Correct 342 ms 72336 KB Output is correct
11 Correct 379 ms 77560 KB Output is correct
12 Correct 208 ms 72652 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 2 ms 948 KB Output is correct
4 Correct 2 ms 980 KB Output is correct
5 Incorrect 2 ms 980 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 2 ms 948 KB Output is correct
4 Correct 2 ms 980 KB Output is correct
5 Incorrect 2 ms 980 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 2 ms 948 KB Output is correct
4 Correct 2 ms 980 KB Output is correct
5 Incorrect 2 ms 980 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 310 ms 72112 KB Output is correct
2 Correct 314 ms 72108 KB Output is correct
3 Correct 354 ms 72084 KB Output is correct
4 Correct 363 ms 83592 KB Output is correct
5 Correct 342 ms 72396 KB Output is correct
6 Correct 461 ms 83208 KB Output is correct
7 Correct 481 ms 83176 KB Output is correct
8 Correct 451 ms 83324 KB Output is correct
9 Correct 387 ms 82080 KB Output is correct
10 Correct 429 ms 82892 KB Output is correct
11 Correct 426 ms 82564 KB Output is correct
12 Correct 434 ms 82956 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 292 ms 72076 KB Output is correct
3 Correct 324 ms 72112 KB Output is correct
4 Correct 365 ms 72064 KB Output is correct
5 Correct 342 ms 73232 KB Output is correct
6 Correct 320 ms 74304 KB Output is correct
7 Correct 338 ms 74576 KB Output is correct
8 Correct 363 ms 83532 KB Output is correct
9 Correct 388 ms 83348 KB Output is correct
10 Correct 342 ms 72336 KB Output is correct
11 Correct 379 ms 77560 KB Output is correct
12 Correct 208 ms 72652 KB Output is correct
13 Correct 0 ms 340 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 2 ms 948 KB Output is correct
16 Correct 2 ms 980 KB Output is correct
17 Incorrect 2 ms 980 KB Output isn't correct
18 Halted 0 ms 0 KB -