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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#640637#8551. DFS Order 5zhenghanyunWA 21ms5680kbC++142.6kb2024-10-14 14:55:382024-10-14 14:55:39

Judging History

你现在查看的是最新测评结果

  • [2024-10-14 14:55:39]
  • 评测
  • 测评结果:WA
  • 用时:21ms
  • 内存:5680kb
  • [2024-10-14 14:55:38]
  • 提交

answer

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

typedef long long ll;

const int N = 1e5 + 5;
const int B = 18;

struct edge {
	int to, Next;

	edge() {}
	edge(int to, int Next): to(to), Next(Next) {}
} G[N << 1];

int head[N], cnt;

inline void add_edge(int u, int v) {
	G[++cnt] = edge(v, head[u]);
	head[u] = cnt;
}

int n, q, k, fa[N], dep[N], siz[N], f[N][B];

vector <int> vec, tmp;
bitset <N> vis;

inline void dfs(int u) {
	dep[u] = dep[fa[u]] + 1;
	siz[u] = 1;
	for (int i = head[u]; i; i = G[i].Next) {
		int v = G[i].to;
		if (v != fa[u]) {
			fa[v] = u;
			dfs(v);
			siz[u] += siz[v];
		}
	}
}

inline void init() {
	dfs(1);
	for (int i = 1; i <= n; ++i) {
		f[i][0] = fa[i];
	}
	for (int j = 1; j < B; ++j) {
		for (int i = 1; i <= n; ++i) {
			f[i][j] = f[f[i][j - 1]][j - 1];
		}
	}
}

inline int kfa(int u, int k) {
	for (int i = 0; i < B; ++i) {
		if (k & (1 << i)) {
			u = f[u][i];
		}
	}
	return u;
}

inline bool p(int u, int v) {
	if (!u) {
		return false;
	}
	if (dep[u] > dep[v]) {
		return false;
	}
	return kfa(v, dep[v] - dep[u]) == u;
}

inline bool check(int l, int r) {
	int u = vec[l];
	for (int i = l; i <= r; ++i) {
		if (!p(u, vec[i])) {
			return false;
		}
	}
	return true;
}

inline bool solve() {
	for (int i = 0; i < k - 1; ++i) {
		if (fa[vec[i + 1]] != vec[i] && !p(fa[vec[i + 1]], vec[i])) {
			return false;
		}
		if (p(vec[i + 1], vec[i])) {
			return false;
		}
	}
	int pos = 0;
	while (pos < k) {
		int r = min(k - 1, pos + siz[vec[pos]] - 1);
		if (!check(pos, r)) {
			return false;
		}
		for (int i = pos; i <= r; ++i) {
			if (vis[vec[i]]) {
				return false;
			}
		}
		if (r != k - 1) {
			int u = kfa(vec[pos], dep[fa[vec[r + 1]]] - dep[vec[pos]] - 1);
			vis[u] = true;
			tmp.emplace_back(u);
		}
		pos = r + 1;
	}
	return true;
}

int main() {
	#ifdef LOCAL
		assert(freopen("test.in", "r", stdin));
		assert(freopen("test.out", "w", stdout));
	#endif
	ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
	cin >> n >> q;
	for (int i = 1; i < n; ++i) {
		int u, v;
		cin >> u >> v;
		add_edge(u, v);
		add_edge(v, u);
	}
	init();
	while (q--) {
		cin >> k;
		vec.resize(k);
		bool flg = false;
		for (int i = 0; i < k; ++i) {
			cin >> vec[i];
			flg |= vis[vec[i]];
			vis[vec[i]] = true;
		}
		for (auto u: vec) {
			vis[u] = false;
		}
		if (flg) {
			cout << "No\n";
			continue;
		}
		if (solve()) {
			cout << "Yes\n";
		} else {
			cout << "No\n";
		}
		for (auto u: tmp) {
			vis[u] = false;
		}
		tmp.clear();
	}
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 5672kb

input:

6 7
1 2
1 3
2 4
3 5
2 6
2 4 1
2 4 2
2 4 3
2 4 4
2 4 5
2 4 6
6 1 2 6 4 3 5

output:

No
No
Yes
No
No
Yes
Yes

result:

ok 7 tokens

Test #2:

score: -100
Wrong Answer
time: 21ms
memory: 5680kb

input:

10 100000
7 2
1 7
7 10
8 6
8 7
1 3
4 5
9 5
5 8
8 8 9 7 2 8 1 6 1
4 8 3 5 2
6 7 10 3 9 9 1
1 1
8 10 3 2 9 3 8 7 3
7 5 6 2 8 5 9 1
6 3 4 6 2 1 3
5 8 9 2 4 9
1 3
2 1 5
5 8 5 1 7 9
10 5 2 9 2 6 4 10 6 3 8
3 4 5 8
2 8 4
9 4 10 1 2 4 3 3 6 3
1 3
6 1 1 6 8 3 1
3 7 3 2
3 9 1 5
4 3 7 8 10
9 4 2 3 10 2 5 4 3 ...

output:

No
No
No
Yes
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
Yes
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
Yes
No
No
No
No
No
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No
Yes
Yes
No
No
No
No
Yes
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
No...

result:

wrong answer 20th words differ - expected: 'No', found: 'Yes'