Submission #1109213

#	Time	Username	Problem	Language	Result	Execution time	Memory
1109213		stdfloat	Birthday gift (IZhO18_treearray)	C++17	0 / 100	2 ms	592 KiB

treearray

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

vector<int> d;

vector<vector<int>> E, sp;

void dfs(int x, int p = -1) {
	sp[x][0] = p;
	if (p != -1) d[x] = d[p] + 1;
	for (auto i : E[x])
		if (i != p) dfs(i, x);
}

int lca(int x, int y) {
	if (d[x] < d[y]) swap(x, y);

	for (int i = 19; i >= 0; i--)
		if (d[x] - (1 << i) >= d[y]) x = sp[x][i];

	if (x == y) return x;

	for (int i = 19; i >= 0; i--) {
		if (sp[x][i] != sp[y][i]) {
			x = sp[x][i]; y = sp[y][i];
		}
	}

	return sp[x][0];
}

int main() {
	ios::sync_with_stdio(false); cin.tie(nullptr);

	int n, m, q;
	cin >> n >> m >> q;

	E.assign(n, {});
	for (int i = 0; i < m; i++) {
		int x, y;
		cin >> x >> y; x--; y--;

		E[x].push_back(y);
		E[y].push_back(x);
	}

	assert(n == 5);

	d.assign(n, 0);
	sp.assign(n, vector<int>(20, -1));
	dfs(0);

	for (int i = 1; i < 20; i++) {
		for (int j = 0; j < n; j++)
			if (sp[j][i - 1] != -1) sp[j][i] = sp[sp[j][i - 1]][i - 1];
	}

	vector<int> a(m);
	for (auto &i : a) {
		cin >> i; i--;
	}

	while (q--) {
		int tp;
		cin >> tp;

		if (tp == 1) {
			int ps, v;
			cin >> ps >> v; ps--; v--;
		
			a[ps] = v;
		}
		else {
			int l, r, v;
			cin >> l >> r >> v; l--; r--; v--;

			pair<int, int> ans = {-2, -2};
			for (int i = l; i <= r; i++) {
				if (a[i] == v) {
					ans = {i, i};
					break;
				}

				if (i != r && lca(a[i], a[i + 1]) == v) {
					ans = {i, i + 1};
					break;
				}
			}

			cout << ans.first + 1 << ' ' << ans.second + 1 << '\n';
		}
	}
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 18
• Subtask 3: 0 / 26
• Subtask 4: 0 / 44