Submission #294228

#	Time	Username	Problem	Language	Result	Execution time	Memory
294228		spdskatr	Spring cleaning (CEOI20_cleaning)	C++14	100 / 100	259 ms	26992 KiB

cleaning

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <vector>

using namespace std;

int N, Q, leaf[100005], lvs[100005], depth[100005], evens[100005], jp[18][100005], rawtot, seen[100005];
int sz[100005], ind[100005], offset[100005], cnt, newans;
vector<int> graph[100005], g2[100005];
vector<int> nl, newnodes, comps;

void dfs1(int x, int p) {
	//printf("dfs1(%d, %d)\n", x, p);
	leaf[x] = 1;
	ind[x] = cnt++;
	sz[x] = 1;
	jp[0][x] = p;
	for (int v : graph[x]) {
		if (v != p) {
			leaf[x] = 0;
			depth[v] = depth[x] + 1;
			dfs1(v, x);
			lvs[x] += lvs[v];
			sz[x] += sz[v];
		}
	}
	if (x == 1 && graph[x].size() <= 1) leaf[x] = 1;
	lvs[x] += leaf[x];
}

void dfs2(int x, int p) {
	if (x != 1) rawtot += 1 + ((lvs[x] % 2) ^ 1);
	evens[x] += ((lvs[x] % 2) ^ 1);
	for (int v : graph[x]) {
		if (v != p) {
			evens[v] = evens[x];
			dfs2(v, x);
		}
	}
}

void dfs3(int x, int p) {
	//printf("dfs3(%d, %d)\n", x, p);
	for (int v : g2[x]) {
		dfs3(v, x);
		offset[x] += offset[v];
	}
	if (offset[x] & 1) {
		newans += depth[x] - depth[p] - 2 * (evens[x] - evens[p]);
	}
}

int isanc(int a, int b) {
	return ind[a] <= ind[b] && ind[a] + sz[a] > ind[b];
}

int lca(int u, int v) {
	if (isanc(u, v)) return u;
	if (isanc(v, u)) return v;
	int cur = u;
	for (int i = 17; i >= 0; i--) {
		if (!isanc(jp[i][cur], v)) cur = jp[i][cur];
	}
	return jp[0][cur];
}

int main() {
	scanf("%d %d", &N, &Q);
	for (int i = 0; i < N-1; i++) {
		int u, v;
		scanf("%d %d", &u, &v);
		graph[u].push_back(v);
		graph[v].push_back(u);
	}
	dfs1(1, 1);
	dfs2(1, 1);
	for (int b = 1; b < 18; b++) {
		for (int i = 1; i <= N; i++) {
			jp[b][i] = jp[b-1][jp[b-1][i]];
		}
	}
	for (int q = 0; q < Q; q++) {
		//printf("==========\n");
		int d;
		scanf("%d", &d);
		nl.clear();
		for (int i = 0; i < d; i++) {
			int a;
			scanf("%d", &a);
			nl.push_back(a);
		}
		int createdleaves = 0;
		sort(nl.begin(), nl.end(), [](int l, int r){
			return ind[l] < ind[r];
		});
		for (int i = 0; i < nl.size(); i++) {
			if (i > 0 && nl[i-1] == nl[i]) {
				offset[nl[i]]++;
				createdleaves++;
			} else {
				//printf("new node: %d\n", nl[i]);
				seen[nl[i]] = 1;
				newnodes.push_back(nl[i]);
				if (i == 0) {
					comps.push_back(nl[i]);
				} else {
					int l = lca(nl[i], nl[i-1]);
					if (!seen[l]) newnodes.push_back(l);
					seen[l] = 1;
					if (l != nl[i-1]) {
						while (comps.size() && depth[l] < depth[comps.back()]) {
							if (comps.size() > 1 && depth[comps[comps.size() - 2]] > depth[l]) {
								g2[comps[comps.size() - 2]].push_back(comps.back());
								//printf("Added compressed tree edge %d -> %d\n", comps[comps.size() - 2], comps.back());
							} else {
								g2[l].push_back(comps.back());
								//printf("Added compressed tree edge %d -> %d\n", l, comps.back());
							}
							comps.pop_back();
						}
						if (comps.empty() || comps.back() != l) comps.push_back(l);
					}
					comps.push_back(nl[i]);
				}
				if (!leaf[nl[i]]) createdleaves++;
				offset[nl[i]] = 1 - leaf[nl[i]];
			}
		}
		while (comps.size() > 1) {
			g2[comps[comps.size()-2]].push_back(comps.back());
			//printf("Added compressed tree edge %d -> %d\n", comps[comps.size() - 2], comps.back());
			comps.pop_back();
		}
		newans = rawtot + d;
		dfs3(comps[0], 1);
		if ((createdleaves + lvs[1]) & 1) {
			printf("-1\n");
		} else {
			printf("%d\n", newans);
		}
		// CLEANUP!!!
		newans = 0;
		for (int v : newnodes) {
			//printf("New nodes: %d\n", v);
			g2[v].clear();
			offset[v] = 0;
			seen[v] = 0;
		}
		newnodes.clear();
		comps.clear();
	}
}

Compilation message (stderr)

cleaning.cpp: In function 'int main()':
cleaning.cpp:97:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |   for (int i = 0; i < nl.size(); i++) {
      |                   ~~^~~~~~~~~~~
cleaning.cpp:69:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   69 |  scanf("%d %d", &N, &Q);
      |  ~~~~~^~~~~~~~~~~~~~~~~
cleaning.cpp:72:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   72 |   scanf("%d %d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~~
cleaning.cpp:86:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   86 |   scanf("%d", &d);
      |   ~~~~~^~~~~~~~~~
cleaning.cpp:90:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   90 |    scanf("%d", &a);
      |    ~~~~~^~~~~~~~~~

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 17 / 17
• Subtask 7: 30 / 30