Submission #862583

#	Time	Username	Problem	Language	Result	Execution time	Memory
862583		theshadow_04	Toll (BOI17_toll)	C++14	100 / 100	116 ms	16828 KiB

toll

#include<bits/stdc++.h>

#define F first 
#define S second

using namespace std;

const int maxn = 50005;

struct Query {
	int u, v, id;
};

int n, m, o, k;
vector<pair<int, int> > adj[maxn], rev_adj[maxn];
int ans[maxn], dis[5][maxn][5]; // [start, block, position]

void divide_and_conquer(int l, int r, vector<Query> query) {
	if (l == r) {
		for (auto x : query) {
			ans[x.id] = -1;
		}
		return;
	}
	int mid = (l + r) >> 1;
	for (int i = 0; i < k; ++ i) {
		for (int j = 0; j < k; ++ j) dis[i][mid][j] = 1e9;
		dis[i][mid][i] = 0;
	}
	for (int i = mid; i > l; -- i) {
		for (int j = 0; j < k; ++ j) {
			for (int j1 = 0; j1 < k; ++ j1) dis[j][i - 1][j1] = 1e9;
			for (int j1 = 0; j1 < k; ++ j1) {
				int u = i * k + j1;
				for (auto v : rev_adj[u]) {
					int j2 = v.F % k;
					dis[j][i - 1][j2] = min(dis[j][i - 1][j2], dis[j][i][j1] + v.S);
				}
			}
		}
	}
	for (int i = 0; i < k; ++ i) {
		for (int j = 0; j < k; ++ j) dis[i][mid + 1][j] = 1e9;
		dis[i][mid + 1][i] = 0;
	}
	for (int i = mid + 1; i < r; ++ i) {
		for (int j = 0; j < k; ++ j) {
			for (int j1 = 0; j1 < k; ++ j1) dis[j][i + 1][j1] = 1e9;
			for (int j1 = 0; j1 < k; ++ j1) {
				int u = i * k + j1;
				for (auto v : adj[u]) {
					int j2 = v.F % k;
					dis[j][i + 1][j2] = min(dis[j][i + 1][j2], dis[j][i][j1] + v.S);
				}
			}
		}
	}
	vector<Query> shorter_query[2];
	for (auto p : query) {
		int u = p.u, v = p.v, id = p.id;
		int L = u / k, R = v / k;
		if (L > mid) shorter_query[1].push_back(p);
		else if (R <= mid) shorter_query[0].push_back(p);
		else {
			ans[id] = 1e9;
			for (int i = 0; i < k; ++ i) {
				int u1 = mid * k + i;
				for (auto x : adj[u1]) {
					int v1 = x.F;
					int j = v1 % k;
					ans[id] = min(ans[id], dis[i][L][u % k] + dis[j][R][v % k] + x.S);
				}
			}
			if (ans[id] == 1e9) ans[id] = -1;
		}
	}
	divide_and_conquer(l, mid, shorter_query[0]);
	divide_and_conquer(mid + 1, r, shorter_query[1]);
}

void solve() {
	cin >> k >> n >> m >> o;
	for (int i = 1; i <= m; ++ i) {
		int u, v, w; cin >> u >> v >> w;
		adj[u].push_back({v, w});
		rev_adj[v].push_back({u, w});
	}
	vector<Query> query;
	for (int i = 1; i <= o; ++ i) {
		int u, v; cin >> u >> v;
		query.push_back({u, v, i}); 
	}
	divide_and_conquer(0, (n - 1) / k, query);
	for (int i = 1; i <= o; ++ i) {
		cout << ans[i] << "\n";
	}
}

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    solve();
    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 31 / 31
• Subtask 5: 44 / 44