| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 484019 | MilosMilutinovic | Rainforest Jumps (APIO21_jumps) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
const int N=200050;
const int LOG=20;
int a[N],l[N],r[N],mn[N][LOG],mx[N][LOG],L[N][LOG],st[N][LOG];
int getmx(int l,int r){
int res=0;
for(int i=LOG-1;~i;i--)if(l+(1<<i)-1<=r)res=max(res,st[l][i]),l+=(1<<i);
return res;
}
void init(int n,int* h){
for(int i=1;i<=n;i++)a[i]=h[i-1],st[i][0]=a[i];
for(int j=1;j<LOG;j++)for(int i=1;i+(1<<j)<=n+1;i++)st[i][j]=max(st[i][j-1],st[i+(1<<(j-1))][j-1]);
stack<int> stk;
for(int i=1;i<=n;i++){
while(!stk.empty()&&a[stk.top()]<a[i])stk.pop();
if(!stk.empty())l[i]=stk.top();
else l[i]=0;
stk.push(i);
}
while(stk.size())stk.pop();
for(int i=n;i>=1;i--){
while(!stk.empty()&&a[stk.top()]<a[i])stk.pop();
if(!stk.empty())r[i]=stk.top();
else r[i]=0;
stk.push(i);
}
for(int i=1;i<=n;i++){
if(l[i]==0||a[l[i]]>a[r[i]])mn[i][0]=r[i];
else mn[i][0]=l[i];
if(l[i]==0||a[l[i]]<a[r[i]])mx[i][0]=r[i];
else mx[i][0]=l[i];
L[i][0]=l[i];
}
// for(int i=1;i<=n;i++){
// printf("i:%d l:%d r:%d\n",i,l[i],r[i]);
// }
for(int j=1;j<LOG;j++){
for(int i=1;i<=n;i++){
mn[i][j]=mn[mn[i][j-1]][j-1];
mx[i][j]=mx[mx[i][j-1]][j-1];
L[i][j]=L[L[i][j-1]][j-1];
}
}
}
int minimum_jumps(int A,int B,int C,int D){
A++;B++;C++;D++;
int x=getmx(C,D),pos=B;
for(int i=LOG-1;~i;i--)if(L[pos][i]>=A&&a[L[pos][i]]<x)pos=L[pos][i];
// printf("pos: %d x:%d a[pos]:%d\n",pos,x,a[pos]);
if(a[pos]>x)return -1;
int ans=0;
for(int i=LOG-1;~i;i--){
if(mx[pos][i]>0&&mx[pos][i]<=D)pos=mx[pos][i],ans+=(1<<i);
if(pos>=C)return ans;
}
if(mn[pos][0]==0||mn[pos][0]>D)return -1;
for(int i=LOG-1;~i;i--){
if(mn[pos][i]>0&&mn[pos][i]<=D)pos=mn[pos][i],ans+=(1<<i);
if(pos>=C)return ans;
}
return -1;
}
//int main(){
// int d;
// scanf("%d",&d);
// int A[d];
// for(int i=0;i<d;i++)scanf("%d",&A[i]);
// init(d,A);
// printf("%d\n",minimum_jumps(4,4,6,6));
// printf("%d\n",minimum_jumps(1,3,5,6));
// printf("%d\n",minimum_jumps(0,1,2,2));
// return 0;
//}
/*
7
3 2 1 6 4 5 7
*/