Submission #567436

#	Time	Username	Problem	Language	Result	Execution time	Memory
567436		Bill_00	Rainforest Jumps (APIO21_jumps)	C++14	100 / 100	1360 ms	45572 KiB

jumps

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

int best[200005][25], rightt[200005][25], h[200005], n, tallest[2000000], L[200005];
void update(int id, int l, int r, int pos, int val){
  if(h[val] > h[tallest[id]]){
    tallest[id] = val;
  }
  if(l == r){
    return;
  }
  int m = l + r >> 1;
  if(m >= pos){
    update(id * 2, l, m, pos, val);
  }
  else update(id * 2 + 1, m + 1, r, pos, val);
}

int query(int id, int l, int r, int lef, int rig){
  if(lef > rig) return 200004;
  if(r < lef || rig < l) return 200004;
  if(lef <= l && r <= rig) return tallest[id];
  int m = l + r >> 1;
  int lll = query(id * 2, l, m, lef, rig);
  int rrr = query(id * 2 + 1, m + 1, r, lef, rig);
  return (h[lll] > h[rrr] ? lll : rrr);
}

void init(int N, vector<int> H){
  n = N;
  for(int i = 1; i <= n; i++){
    h[i] = H[i - 1];
    update(1, 1, n, i, i);
  }
  stack<int> s, t;
  h[n + 1] = 1e9;
  s.push(n + 1);
  for(int i = n; i >= 1; i--){
    while(h[s.top()] < h[i]){
      s.pop();
    }
    rightt[i][0] = s.top();
    s.push(i);
  }
  t.push(0);
  h[0] = 1e9;
  for(int i = 1; i <= n; i++){
    while(h[t.top()] < h[i]){
      t.pop();
    }
    L[i] = t.top();
    t.push(i);
  }
  for(int i = 1; i <= n; i++){
    if(h[L[i]] < 1e9 && h[rightt[i][0]] < 1e9){
      best[i][0] = (h[L[i]] > h[rightt[i][0]] ? L[i] : rightt[i][0]);
    }
    else{
      if(h[L[i]] < 1e9){
        best[i][0] = L[i];
      }
      else{
        if(h[rightt[i][0]] < 1e9){
          best[i][0] = rightt[i][0];
        }
        else best[i][0] = 0;
      }
    }
  }
  rightt[n + 1][0] = n + 1;
  for(int j = 1; j <= 20; j++){
    for(int i = 0; i <= n + 1; i++){
      rightt[i][j] = rightt[rightt[i][j - 1]][j - 1];
      best[i][j] = best[best[i][j - 1]][j - 1];
    }
  }
}

int minimum_jumps(int A, int B, int C, int D){
  A++, B++, C++, D++;
  int x = query(1, 1, n, B + 1, C - 1);
  int y = query(1, 1, n, C, D);
  // cout << x << ' ' << y << '\n';
  if(h[x] > h[y]) return -1;
  if(h[B] > h[y]) return -1;
  int z = query(1, 1, n, A, B);
  if(h[z] > h[y]){
    int lll = A, rrr = B, pos;
    while(lll < rrr){
      int mmm = lll + rrr >> 1;
      pos = query(1, 1, n, mmm, B);
      if(h[pos] > h[y]){
        lll = mmm + 1;
      }
      else rrr = mmm;
    }
    pos = query(1, 1, n, lll, B);
    int ans = 0;
    for(int i = 20; i >= 0; i--){
      if(C > rightt[pos][i]){
        ans += (1 << i);
        pos = rightt[pos][i];
      } 
    }
    return ans + 1;
  }
  else{
    int ans = 0;
    int pos = z;
    // cout << pos << ' ' << x << '\n';
    for(int i = 20; i >= 0; i--){
      if(h[best[pos][i]] < h[x]){
        pos = best[pos][i];
        ans += (1 << i);
      }
    }
    // cout << best[pos][0] << ' ' << ans << '\n';
    if(h[best[pos][0]] < h[y]){
      if((best[pos][0] >= C && best[pos][0] <= D) || (rightt[pos][0] >= C && rightt[pos][0] <= D)) ans++;
      else ans += 2;
    }
    else{
      for(int i = 20; i >= 0; i--){
        // cout << pos << '\n';
        if(C > rightt[pos][i]){
          ans += (1 << i);
          pos = rightt[pos][i];
        }
      }
      ans++;
    }
    return ans;
  }
}

Compilation message (stderr)

jumps.cpp: In function 'void update(int, int, int, int, int)':
jumps.cpp:14:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   14 |   int m = l + r >> 1;
      |           ~~^~~
jumps.cpp: In function 'int query(int, int, int, int, int)':
jumps.cpp:25:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |   int m = l + r >> 1;
      |           ~~^~~
jumps.cpp: In function 'int minimum_jumps(int, int, int, int)':
jumps.cpp:92:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   92 |       int mmm = lll + rrr >> 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