Submission #737500

#TimeUsernameProblemLanguageResultExecution timeMemory
737500keisuke6Rainforest Jumps (APIO21_jumps)C++14
0 / 100
4078 ms13904 KiB
#include "jumps.h"

#include <vector>
#include <queue>
using namespace std;
vector<vector<int>> G(200100);
int n;
struct SEG{
private:
  int n;
  vector<int> node;
public:
  SEG(int N){
    n = 1;
    while(n < N) n *= 2;
    node.resize(2*n-1,0);
  }
  void update(int i, int x){
    i += n-1;
    node[i] = x;
    while(i > 0){
      i--;
      i /= 2;
      node[i] = max(node[2*i+1],node[2*i+2]);
    }
    return;
  }
  int query(int a, int b, int k = 0, int l = 0, int r = -1){
    if(r < 0) r = n;
    if(a >= b) return 0;
    if(b <= l || r <= a) return 0;
    if(a <= l && r <= b) return node[k];
    int vl = query(a,b,2*k+1,l,(l+r)/2);
    int vr = query(a,b,2*k+2,(l+r)/2,r);
    return max(vl,vr);
  }
};
SEG seg(200100);
void init(int N, std::vector<int> H) {
  n = N;
  for(int i=0;i<N;i++) seg.update(i,H[i]);
  for(int i=0;i<N;i++){
    if(seg.query(0,i) > H[i]){
      int ac = 0, wa = i;
      while(wa-ac > 1){
        int wj = (ac+wa)/2;
        if(seg.query(wj,i) > H[i]) ac = wj;
        else wa = wj;
      }
      G[i].push_back(ac);
    }
    if(seg.query(i+1,N)){
      int ac = N, wa = i;
      while(ac-wa > 1){
        int wj = (ac+wa)/2;
        if(seg.query(i+1,wj) > H[i]) ac = wj;
        else wa = wj;
      }
      G[i].push_back(wa);
    }
  }
  return;
}

int minimum_jumps(int A, int B, int C, int D) {
  vector<int> dist(n,1e9);
  queue<int> q;
  for(int i=A;i<=B;i++){
    dist[i] = 0;
    q.push(i);
  } 
  while(!q.empty()){
    int pos = q.front();
    q.pop();
    for(int x:G[pos]){
      if(dist[x] != 1e9) continue;
      dist[x] = dist[pos] + 1;
      q.push(x);
    }
  }
  int ans = 1e9;
  for(int i=C;i<=D;i++) ans = min(ans,dist[i]);
  return (ans == 1e9 ? -1 : ans);
}
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