Submission #950144

#	Time	Username	Problem	Language	Result	Execution time	Memory
950144		vjudge1	Triple Jump (JOI19_jumps)	C++17	19 / 100	440 ms	152936 KiB

jumps

#include<bits/stdc++.h>

using namespace std;

const int N = (int)5e5+7;
const int M = (int)2e5+7;
const int inf = (int)1e9+7;

int n, q, a[N];
int dp[5003][5003], mx[5003][5003];
int oo[M][20], lo[M];
pair<int, int> pref[N], suf[N];

int get(int l, int r) {
	if(l>r) {
		return -inf;
	}
	int x = lo[r-l+1];
	return max(oo[l][x], oo[r-(1<<x)+1][x]);
}

void solve3() {
	cin >> q >> q >> q;
	for(int i = 2; i < M; ++i) {
		lo[i] = lo[i/2]+1;
	}
	for(int i = 1; i <= n; ++i) {
		oo[i][0] = a[i];
		pref[i] = max(pref[i-1], {a[i], i});
	}
	for(int i = n; i >= 1; --i) {
		suf[i] = max(suf[i+1], {a[i], i});
	}
	for(int i = 2; i < 18; ++i) {
		for(int j = 1; j <= n-(1<<i)+1; ++j) {
			oo[i][j] = max(oo[i][j], oo[i+(1<<(j-1))][j-1]); 
		}
	}
	int ans = 0;
	for(int i = 2; i < n; ++i) {
		int nxt = suf[i+1].second;
		ans = max(ans, a[i]+a[nxt]+get(max(1, i-(nxt-i)), i-1));
		nxt = pref[i-1].second;
		if(i+(i-nxt)<=n) {
			ans = max(ans, a[i]+a[nxt]+get(i+(i-nxt), n));
		}
	}
		
	cout << ans;
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cin >> n;
	for(int i = 1; i <= n; ++i) {
		cin >> a[i];
	} 
	if(n>5000) {
		solve3();
		return 0;
	}
	for(int i = 1; i <= n; ++i) {
		for(int j = i; j <= n; ++j) {
			mx[i][j] = max(mx[i][j-1], a[j]);
		}
	}
	for(int len = 3; len <= n; ++len) {
		for(int i = 1; i <= n-len+1; ++i) {
			int j = i+len-1;
			dp[i][j]=max(dp[i+1][j], dp[i][j-1]);
			int cur = a[i]+a[j];
			int m = (i+j)/2;
			cur += mx[i+1][m];
			dp[i][j] = max(dp[i][j], cur);
		}
	}
	cin >> q;
	while(q--) {
		int l, r;
		cin >> l >> r;
		cout << dp[l][r] << "\n";
	}
    return 0;
}

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