Submission #536346

#	Time	Username	Problem	Language	Result	Execution time	Memory
536346		skittles1412	Joker (BOI20_joker)	C++17	0 / 100	72 ms	7456 KiB

Joker

#include "bits/extc++.h"

using namespace std;

template <typename T>
void dbgh(const T& t) {
	cerr << t << endl;
}

template <typename T, typename... U>
void dbgh(const T& t, const U&... u) {
	cerr << t << " | ";
	dbgh(u...);
}

#ifdef DEBUG
#define dbg(...)                                           \
	cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]" \
		 << ": ";                                          \
	dbgh(__VA_ARGS__)
#else
#define cerr   \
	if (false) \
	cerr
#define dbg(...)
#endif

#define endl "\n"
#define long int64_t
#define sz(x) int((x).size())

namespace s1 {

const int maxn = 2e3 + 5;

int bl, br, vis[maxn];
bool bad;
vector<pair<int, int>> graph[maxn];

void dfs(int u, int b) {
	if (vis[u]) {
		bad |= vis[u] != b;
		return;
	}
	vis[u] = b;
	for (auto& [v, i] : graph[u]) {
		if (i < bl || br < i) {
			dfs(v, b ^ 1);
		}
	}
}

void solve(int n, int m, int q) {
	for (int i = 0; i < m; i++) {
		int u, v;
		cin >> u >> v;
		u--;
		v--;
		graph[u].emplace_back(v, i);
		graph[v].emplace_back(u, i);
	}
	while (q--) {
		cin >> bl >> br;
		bl--;
		br--;
		bad = false;
		memset(vis, 0, sizeof(vis));
		for (int i = 0; i < n; i++) {
			if (!vis[i]) {
				dfs(i, 0);
			}
		}
		if (bad) {
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
}

}  // namespace s1

const int maxn = 2e5 + 5;

struct DSU {
	bool bip;
	vector<int> p, par;

	explicit DSU(int n) : bip(true), p(n, -1), par(n) {}

	pair<int, bool> find(int u) {
		if (p[u] < 0) {
			return {u, false};
		}
		auto [v, vp] = find(p[u]);
		p[u] = v;
		par[u] ^= vp;
		return {p[u], par[u]};
	}

	void merge(int xu, int xv) {
		auto [u, pu] = find(xu);
		auto [v, pv] = find(xv);
		if (u == v) {
			bip &= pu != pv;
			return;
		}
		if (p[u] < p[v]) {
			swap(u, v);
		}
		p[v] += p[u];
		p[u] = v;
		par[u] ^= 1;
	}
};

int n, m;
vector<pair<int, int>> edges;

int solve(int ol) {
	DSU dsu(n);
	for (int i = 0; i < ol; i++) {
		auto& [u, v] = edges[i];
		dsu.merge(u, v);
	}
	for (int i = m - 1; i >= ol; i--) {
		auto& [u, v] = edges[i];
		dsu.merge(u, v);
		if (!dsu.bip) {
			return i;
		}
	}
	return -1;
}

void solve() {
	int q;
	cin >> n >> m >> q;
	edges.resize(m);
	for (auto& [u, v] : edges) {
		cin >> u >> v;
		u--;
		v--;
	}
	int ans[n];
	fill(ans, ans + n, -1e9);
	while (q--) {
		int l, r;
		cin >> l >> r;
		l--;
		r--;
		if (ans[l] == -1e9) {
			ans[l] = solve(l);
		}
		dbg(ans[l]);
		if (r < ans[l]) {
			cout << "YES" << endl;
		} else {
			cout << "NO" << endl;
		}
	}
}

int main() {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	cin.exceptions(ios::failbit);
	solve();
}

• Subtask 1: 0 / 6
• Subtask 2: 0 / 8
• Subtask 3: 0 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29