Submission #1125292

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125292		mychecksedad	Fire (BOI24_fire)	C++17	100 / 100	200 ms	37980 KiB

Main

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
#define ff first
#define ss second
#define pii pair<int,int>
#define vi vector<int>
const int N = 1e6+100, M = 1e5+10, K = 22, MX = 30;


int n, m;
array<int, 2> a[N];
int go[N][K];
void solve(){
  cin >> n >> m;
  for(int i = 1; i <= n; ++i){
    cin >> a[i][0] >> a[i][1];
    // --a[i][0];
    if(a[i][0] > a[i][1]) a[i][1] += m;
  }
  sort(a+1, a+1+n, [&](const array<int, 2> &x, const array<int, 2> &y){
    return pii{x[1], x[0]} < pii{y[1], y[0]};
  });
  // for(int i = 1; i <= n; ++i){
  //   cout << a[i][0] << ' ' << a[i][1] << '\n';
  // }
  set<pair<int, int>> S;
  set<pair<int, int>> R;
  for(int i = n; i >= 1; --i){
    auto ti = R.end();
    while(!R.empty() && (*prev(ti)).ff > a[i][1]){
      auto k = *prev(ti);
      S.erase(S.find(pii{a[k.ss][1], k.ss}));
      R.erase(prev(ti));
      ti = R.end();
    }
    auto it = S.end();
    if(S.empty()) go[i][0] = i;
    else go[i][0] = (*prev(it)).ss;
    S.insert({a[i][1], i});
    R.insert({a[i][0], i});
    // cout << go[i][0] << ' ';
  }
  for(int j = 1; j < K; ++j){
    for(int i = 1; i <= n; ++i){
      go[i][j] = go[go[i][j - 1]][j - 1];
    }
  }
  int ans = MOD;
  for(int i = 1; i <= n; ++i){
    int v = i, cur = a[i][1], s = 1;
    for(int j = K-1; j >= 0; --j){
      if(a[go[v][j]][1] < a[i][0] + m) v = go[v][j], s += (1<<j);
    }
    // cout << s << ' ';
    if(a[go[v][0]][1] >= a[i][0] + m){
      ans=min(ans,s+1);
    }
  }
  cout << (ans==MOD?-1:ans);
}


int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  while(tt--){
    solve();
    en;
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
} 

• Subtask 1: 14 / 14
• Subtask 2: 17 / 17
• Subtask 3: 9 / 9
• Subtask 4: 13 / 13
• Subtask 5: 21 / 21
• Subtask 6: 26 / 26