Submission #1159231

#	Time	Username	Problem	Language	Result	Execution time	Memory
1159231		alexander707070	Triple Jump (JOI19_jumps)	C++20	46 / 100	434 ms	72904 KiB

jumps

#include<bits/stdc++.h>
#define MAXN 500007
using namespace std;

const int inf=1e9;

struct tower{
	int val,pos;

	inline friend bool operator < (tower a,tower b){
		return a.val>b.val;
	}
};

int n,ans,q,l,r;
tower a[MAXN];

int maxs[MAXN][20];
int lg[MAXN];
int dp[5007][5007];

void calc(){
	for(int j=1;j<20;j++){
		for(int i=1;i+(1<<j)-1<=n;i++){
			maxs[i][j]=max( maxs[i][j-1] , maxs[i+(1<<(j-1))][j-1] );
		}
	}

	for(int i=2;i<=n;i++)lg[i]=lg[i/2]+1;
}

int getmax(int l,int r){
	if(l>r)return -inf;

	int len=r-l+1;
	return max( maxs[l][lg[len]] , maxs[r-(1<<lg[len])+1][lg[len]] );
}

void solve_fast(){
	sort(a+1,a+n+1);

	for(int i=1;i<=min(n,20);i++){
		for(int f=1;f<=n;f++){
			if(i==f)continue;

			int c=a[i].pos,d=a[f].pos;

			if(c>d)swap(c,d);
			ans=max(ans,a[i].val + a[f].val + getmax(c+1,(c+d)/2));
			ans=max(ans,a[i].val + a[f].val + getmax(max(c-(d-c),1),c-1));
			ans=max(ans,a[i].val + a[f].val + getmax(d+(d-c),n));
		}
	}

	cout<<ans<<"\n";
}

int main(){

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);

	cin>>n;

	for(int i=1;i<=n;i++){
		cin>>a[i].val;
		a[i].pos=i;

		maxs[i][0]=a[i].val;
	}
	calc();

	if(n>5000){
		solve_fast();
		return 0;
	}

	for(int len=3;len<=n;len++){
		for(int i=1;i+len-1<=n;i++){
			int f=i+len-1;

			if(i+2==f)dp[i][f]=a[i].val+a[i+1].val+a[i+2].val;
			else{
				dp[i][f]=max(dp[i][f-1],dp[i+1][f]);
				dp[i][f]=max(dp[i][f],a[i].val+a[f].val+getmax(i+1,(i+f)/2));
			}
		}
	}

	cin>>q;

	for(int i=1;i<=q;i++){
		cin>>l>>r;
		cout<<dp[l][r]<<"\n";
	}

	return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 14 / 14
• Subtask 3: 27 / 27
• Subtask 4: 0 / 54