Submission #1210136

#	Time	Username	Problem	Language	Result	Execution time	Memory
1210136		mychecksedad	Railway Trip (JOI17_railway_trip)	C++20	100 / 100	105 ms	47304 KiB

railway_trip

/* 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;

struct Fenwick{
  vector<int> t;
  Fenwick(int n){
    t.resize(n + 1);
  }
  void add(int v){
    while(v < t.size()){
      t[v]++;
      v += v & -v;
    }
  }
  int get(int v){
    int res=0;
    while(v > 0){
      res+=t[v];
      v -= v&-v;
    }
    return res;
  }
};


int n, k, q, a[N], L[N][K], R[N][K];
vector<int> g[N];
void solve(){
  cin >> n >> k >> q;
  vector<vi> C(k + 1);
  for(int i = 1; i <= n; ++i){
    cin >> a[i];
    C[a[i]].pb(i);
  }
  vector<pii> Q;
  for(int i = 1; i <= n; ++i){
    L[i][0] = i;
    while(Q.size() && Q.back().ff < a[i]) Q.pop_back();
    if(Q.size()){
      L[i][0] = Q.back().ss;
    }
    Q.pb({a[i], i});
  }
  Q.clear();
  for(int i = n; i >= 1; --i){
    R[i][0] = i;
    while(Q.size() && Q.back().ff < a[i]) Q.pop_back();
    if(Q.size()){
      R[i][0] = Q.back().ss;
    }
    Q.pb({a[i], i});
  }
  for(int j = 1; j < K; ++j){
    for(int i = 1; i <= n; ++i){
      L[i][j] = min(L[L[i][j - 1]][j - 1], L[R[i][j - 1]][j - 1]);
      R[i][j] = max(R[R[i][j - 1]][j - 1], R[L[i][j - 1]][j - 1]);
    }
  }

  for(int i = 1; i <= q; ++i){
    int x, y; cin >> x >> y;
    if(y < x) swap(y, x);
    int l = x, r = x;
    int ans = 0;
    for(int j = K-1; j >= 0; --j){
      if(max(R[r][j], R[l][j]) < y){
        tie(l, r) = pii{min(L[l][j], L[r][j]), max(R[l][j], R[r][j])};
        ans += 1<<j;
      }
    }

    int c = r;
    l = r = y;
    for(int j = K-1; j >= 0; --j){
      if(min(L[r][j], L[l][j]) > c){
        tie(l, r) = pii{min(L[l][j], L[r][j]), max(R[l][j], R[r][j])};
        ans += 1<<j;
      }
    }
    cout << ans << '\n';
  }
}


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: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 25 / 25
• Subtask 4: 55 / 55