Submission #980758

#	Time	Username	Problem	Language	Result	Execution time	Memory
980758		Mr_Husanboy	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	1123 ms	57888 KiB

jumps

#include "jumps.h"
#include<bits/stdc++.h>

using namespace std;
#define ll long long
#define ff first
#define ss second
const int mod = 1e9 + 7;
const int inf = 1e9;
const int logn = 20;

template<typename T>
int len(T &a){return a.size();}


vector<vector<int>> up, low;

int n;
bool sub1 = 1;



vector<int> h; vector<int> pos;

struct SparseT{
  vector<vector<int>> t;
  int n, logn;
  int join(int a, int b){
    return max(a,b);
  }

  int neutral(){
    return 0;
  }

  SparseT (){}

  SparseT (int _n){
    init(_n);
  }

  SparseT (vector<int> &a){
    build(a);
  }

  void init(int _n){
    n = _n;
    logn = 32 - __builtin_clz(n);
    t.assign(_n, vector<int>(logn, neutral()));
  }

  void build(vector<int> &a){
    init((int)(a.size()));
    for(int i = 0; i < n; i ++){
      t[i][0] = a[i];
    }

    for(int i = 1; i < logn; i ++){
      for(int j = 0; j + (1 << i) <= n; j ++){
        t[j][i] = join(t[j][i - 1], t[j + (1 << (i - 1))][i - 1]);
      }
    }
  }

  int get(int l, int r){
    if(l > r) return neutral();
    int k = 31 - __builtin_clz(r - l + 1);
    return join(t[l][k], t[r - (1 << k) + 1][k]); 
  }
} t;


void init(int N, vector<int> H) {
  h = H;
  n = N;
  pos.resize(n);

  for(int i = 0; i < n; i ++) h[i] --;
  for(int i = 0; i < n; i ++) pos[h[i]] = i;
  vector<int> st;
  vector<int> lef(n), rig(n);
  for(int i = 0; i < n; i ++){
    if(h[i] != i + 1) sub1 = 0;
    while(!st.empty() && st.back() <= h[i]) st.pop_back();
    if(st.empty()) lef[i] = -1;
    else lef[i] = st.back();
    st.push_back(h[i]);
  }
  if(sub1) return;
  st.clear();
  for(int i = n - 1; i >= 0; i --){
    while(!st.empty() && st.back() <= h[i]) st.pop_back();
    if(st.empty()) rig[i] = -1;
    else rig[i] = st.back();
    st.push_back(h[i]);
  }

  up.assign(logn, vector<int> (n, -1));
  low.assign(logn, vector<int> (n, -1));

  for(int i = 0; i < n; i ++){
    up[0][h[i]] = max(lef[i], rig[i]);
  }
  t.build(h);
  // first max, then min
  for(int j = 1; j < logn; j ++){
    for(int i = 0; i < n; i ++){
      if(up[j - 1][i] == -1) continue;
      //cout << (up[j][i]) << endl;
      up[j][i] = up[j - 1][up[j - 1][i]];
    }
  }

  for(int i = 0; i < n; i ++){
    if(lef[i] == -1 && rig[i] == -1) continue;
    if(lef[i] == -1) low[0][h[i]] = rig[i];
    else if(rig[i] == -1) low[0][h[i]] = rig[i];
    else low[0][h[i]] = min(rig[i], lef[i]);
  }

  for(int j = 1; j < logn; j ++){
    for(int i = 0; i < n; i ++){
      if(low[j - 1][i] == -1) continue;
      low[j][i] = low[j - 1][low[j - 1][i]];
    }
  }
}

int minimum_jumps(int A, int B, int C, int D) {
  if(sub1) return C - B;
  int obst = t.get(B, C - 1);
  int mxx = t.get(C, D);
  if(mxx <= obst) return -1;


  int l = A - 1, r = B;
  while(r - l > 1){
    int m = (l + r) / 2;
    if(t.get(m, C - 1) < mxx){
      r = m;
    }else l = m;
  }
  int ans = 0;
  int st = t.get(r, B);
  //cout << st + 1 << endl;
  if(st > obst){
    return 1;
  }
  for(int j = logn - 1; j >= 0; j --){
    if(up[j][st] != -1 && up[j][st] <= obst){
      ans += 1 << j;
      st = up[j][st];
    }
  }
  //cout << st + 1 << endl;

  if(st == obst){
    return ans + 1;
  }
  if(up[0][st] <= mxx){
    if(C <= pos[up[0][st]] && pos[up[0][st]] <= D){
      return ans + 1;
    }
    return ans + 2;
  }
  for(int j = logn - 1; j >= 0; j --){
    if(low[j][st] != -1 && low[j][st] <= obst){
      st = low[j][st];
      ans += 1 << j;
    }
  }
  return ans + 1;
}

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 13 / 13
• Subtask 4: 12 / 12
• Subtask 5: 23 / 23
• Subtask 6: 21 / 21
• Subtask 7: 19 / 19