Submission #484113

#	Time	Username	Problem	Language	Result	Execution time	Memory
484113		MilosMilutinovic	Rainforest Jumps (APIO21_jumps)	C++14	100 / 100	1422 ms	161692 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
const int N=200050;
const int LOG=25;
int a[N],l[N],r[N],L[N][LOG],st[N][LOG];
tuple<int,int,int> mn[N][LOG],mx[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,vector<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(r[i]!=0&&(l[i]==0||a[l[i]]>a[r[i]]))mn[i][0]={r[i],r[i],r[i]};
		else mn[i][0]={l[i],r[i],r[i]};
		if(r[i]!=0&&(l[i]==0||a[l[i]]<a[r[i]]))mx[i][0]={r[i],r[i],r[i]};
		else mx[i][0]={l[i],r[i],r[i]};
		L[i][0]=l[i];
	}
	for(int j=1;j<LOG;j++){
		for(int i=1;i<=n;i++){
			mn[i][j]=mn[get<0>(mn[i][j-1])][j-1];
			mx[i][j]=mx[get<0>(mx[i][j-1])][j-1];
			L[i][j]=L[L[i][j-1]][j-1];
			get<1>(mn[i][j])=max(get<1>(mn[i][j]),get<1>(mn[i][j-1]));
			get<1>(mx[i][j])=max(get<1>(mx[i][j]),get<1>(mx[i][j-1]));
			get<2>(mn[i][j])=max(get<2>(mn[i][j]),get<2>(mn[i][j-1]));
			get<2>(mx[i][j])=max(get<2>(mx[i][j]),get<2>(mx[i][j-1]));
		}
	}
}
//bool check(int A,int B){
//	for(int i=LOG-1;~i;i--)if(mn[A][i]!=0&&a[mn[A][i]]<=a[B])A=mn[A][i];
//	return A==B;
//}
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&&r[L[pos][i]]!=0&&r[L[pos][i]]<=D)pos=L[pos][i];
	int ans=0;
	for(int i=LOG-1;~i;i--){
		if(get<0>(mx[pos][i])>0&&get<1>(mx[pos][i])<C&&r[get<0>(mx[pos][i])]!=0&&r[get<0>(mx[pos][i])]<=D&&get<2>(mx[pos][i])<=D)pos=get<0>(mx[pos][i]),ans+=(1<<i);
	}
	for(int i=LOG-1;~i;i--){
		if(get<0>(mn[pos][i])>0&&get<1>(mn[pos][i])<C&&r[get<0>(mn[pos][i])]!=0&&r[get<0>(mn[pos][i])]<=D&&get<2>(mn[pos][i])<=D)pos=get<0>(mn[pos][i]),ans+=(1<<i);
		assert(pos<=D);
	}
	if(r[pos]>=C&&r[pos]<=D)ans++,pos=r[pos];
	if(pos>=C&&pos<=D)return ans;
	return -1;
}
//int main(){
//	int d;
//	scanf("%d",&d);
//	vector<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
*/

Compilation message (stderr)

jumps.cpp: In function 'int minimum_jumps(int, int, int, int)':
jumps.cpp:55:6: warning: unused variable 'x' [-Wunused-variable]
   55 |  int x=getmx(C,D),pos=B;
      |      ^

• 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