Submission #744743

#	Time	Username	Problem	Language	Result	Execution time	Memory
744743		pavement	Bitaro's travel (JOI23_travel)	C++17	100 / 100	498 ms	48848 KiB

travel

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

#define pb push_back
#define mp make_pair
#define mt make_tuple
#define int long long

using ii = pair<int, int>;
using iii = tuple<int, int, int>;

int N, Q, X[200005], Y[200005], Z[200005];

struct node0 {
	node0 *left, *right;
	int S, E, val;
	node0(int _s, int _e) : S(_s), E(_e) {
		if (S == E) {
			val = Z[S];
			return;
		}
		int M = (S + E) >> 1;
		left = new node0(S, M);
		right = new node0(M + 1, E);
		val = max(left->val, right->val);
	}
	int qry(int p, int v) {
		if (p < S) return 0;
		if (E <= p) {
			if (val < v) return 0;
			if (S == E) return S;
			if (right->val >= v) return right->qry(p, v);
			else return left->qry(p, v);
		}
		auto t = right->qry(p, v);
		if (t) return t;
		return left->qry(p, v);
	}
} *root0;

struct node1 {
	node1 *left, *right;
	int S, E, val;
	node1(int _s, int _e) : S(_s), E(_e) {
		if (S == E) {
			val = Y[S];
			return;
		}
		int M = (S + E) >> 1;
		left = new node1(S, M);
		right = new node1(M + 1, E);
		val = max(left->val, right->val);
	}
	int qry(int p, int v) {
		if (p > E) return N + 1;
		if (p <= S) {
			if (val < v) return N + 1;
			if (S == E) return S;
			if (left->val >= v) return left->qry(p, v);
			else return right->qry(p, v);
		}
		auto t = left->qry(p, v);
		if (t != N + 1) return t;
		return right->qry(p, v);
	}
} *root1;

main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> N;
	for (int i = 1; i <= N; i++) {
		cin >> X[i];
	}
	for (int i = 1; i <= N; i++) {
		Y[i] = X[i] - 2 * X[i - 1];
		Z[i] = 2 * X[i + 1] - X[i];
	}
	root0 = new node0(1, N);
	root1 = new node1(1, N);
	cin >> Q;
	for (int S; Q--; ) {
		cin >> S;
		int cur = 0;
		int pos = lower_bound(X + 1, X + 1 + N, S) - X;
		int x = (int)-1e16, y = (int)1e16;
		if (pos <= N) {
			y = X[pos];
		}
		if (pos > 1) {
			x = X[pos - 1];
		}
		cur += min(S - x, y - S);
		if (S - x <= y - S) {
			S = pos - 1;
		} else {
			S = pos;
		}
		int l = S, r = S;
		//~ cout << "@ " << S << '\n';
		while (l > 1 || r < N) {
			// decide which direction
			int x = (l == 1 ? (int)1e16 : llabs(X[S] - X[l - 1]));
			int y = (r == N ? (int)1e16 : llabs(X[S] - X[r + 1]));
			if (x <= y) {
				// left
				// find maximum j < l such that
				// Z[j] >= y + X[S] + 1
				//~ int j = root[0]->qry(1, l - 1, y + X[S] + 1) + 1;
				int j = root0->qry(l - 1, y + X[S] + 1) + 1;
				// l --> j
				cur += X[S] - X[j];
				l = S = j;
			} else {
				// right
				// find minimum j > r such that
				// Y[j] >= x - X[S]
				//~ int j = root[1]->qry(r + 1, N, x - X[S]) - 1;
				int j = root1->qry(r + 1, x - X[S]) - 1;
				// r --> j
				cur += X[j] - X[S];
				r = S = j;
			}
			//~ cout << "@ " << S << ' ' << l << ' ' << r << ' ' << cur << '\n';
		}
		cout << cur << '\n';
	}
}

Compilation message (stderr)

travel.cpp:68:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   68 | main() {
      | ^~~~

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