Submission #1308793

#	Time	Username	Problem	Language	Result	Execution time	Memory
1308793		thuhienne	Bitaro's travel (JOI23_travel)	C++20	100 / 100	610 ms	33132 KiB

travel

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

using ll = long long;

#define re exit(0);

const int LOG = 18;

int n,x[200009];
int sparse1[200009][LOG + 1],sparse2[200009][LOG + 1];

ll calc(int l,int r,int pos) {
	if (l == 0) return x[n] - pos;
	if (r == n + 1) return pos - x[1];
	
	int left = pos - x[l],right = x[r] - pos;
	
	if (left <= right) {
		//vi tri cach xa nhat ma
		//x_i - x_i-1 <= x_r - x_i
		//2*x_i - x_i-1 <= x_r
		
		if (l == 1 || 2*x[l] - x[l - 1] > x[r]) return left + calc(l - 1,r,x[l]);
		
		int temp = l;
		for (int i = 0;i <= LOG;i++) if (temp - (1 << i) >= 2 && sparse1[temp - (1 << i)][i] <= x[r]) {
			temp -= (1 << i);
		}
		
		return pos - x[temp - 1] + calc(temp - 2,r,x[temp - 1]);
		
	} else {
		//vi tri cach xa nhat ma
		//x_i+1 - x_i < x_i - x_l
		//2*x_i - x_i+1 > x_l
		
		if (r == n || 2*x[r] - x[r + 1] <= x[l]) return right + calc(l,r + 1,x[r]); 
		
		int temp = r;
		for (int i = 0;i <= LOG;i++) if (temp + (1 << i) < n && sparse2[temp + 1][i] > x[l]) {
			temp += (1 << i);
		}
		
		return x[temp + 1] - pos + calc(l,temp + 2,x[temp + 1]);
		
	}
	
}

int main() {
  ios_base::sync_with_stdio(0);cin.tie(nullptr);

	cin >> n;
	for (int i = 1;i <= n;i++) {
		cin >> x[i];
	}
	for (int i = 1;i <= n;i++) {
		sparse1[i][0] = 2 * x[i] - x[i - 1];
		sparse2[i][0] = 2 * x[i] - x[i + 1];
	}
	
	for (int j = 1;j <= LOG;j++) {
		for (int i = 1;i + (1 << j) - 1 <= n;i++) {
			sparse1[i][j] = max(sparse1[i][j - 1],sparse1[i + (1 << (j - 1))][j - 1]);
			sparse2[i][j] = min(sparse2[i][j - 1],sparse2[i + (1 << (j - 1))][j - 1]);
		}
	}
	
	int q;cin >> q;
	while (q--) {
		int pos;cin >> pos;
	
		int l = upper_bound(x + 1,x + 1 + n,pos) - x - 1;
		int r = upper_bound(x + 1,x + 1 + n,pos) - x;
		
		cout << calc(l,r,pos) << '\n';
	}

}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 55 / 55