Submission #106110

#	Time	Username	Problem	Language	Result	Execution time	Memory
106110		mzhao	Mergers (JOI19_mergers)	C++11	0 / 100	30 ms	23936 KiB

mergers

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

#ifdef DEBUG
#define D(x...) printf(x)
#else
#define D(x...)
#endif

#define MN 500100

int N, K, S[MN];
vector<int> adj[MN];

int tot[MN], cnt[MN], ans, num[MN];
bool bad[MN], sub[MN];

void dfs(int n, int p) {
	int cur[8];
	for (int i = 1; i <= K; i++) cur[i] = cnt[i];
	cnt[S[n]]++;
	for (int i : adj[n]) if (i != p) {
		dfs(i, n);
		sub[n] |= sub[i] || bad[i];
	}
	for (int i = 1; i <= K; i++) cur[i] = cnt[i]-cur[i];
	if (n == 1) return;
	bool f = 1;
	for (int i = 1; i <= K; i++) if (cur[i] && cur[i] != tot[i]) {
		f = 0;
		break;
	}
	bad[n] = f;
}

void dfs2(int n, int p, bool b) {
	b |= bad[n];
	if (!sub[n]) {
		ans += b;
		num[n] = 1;
		return;
	}
	for (int i : adj[n]) if (i != p) dfs2(i, n, b);
}

bool extra;

void dfs3(int n, int p) {
	for (int i : adj[n]) if (i != p) {
		dfs3(i, n);
		num[n] += num[i];
	}
	if (num[n] == ans && bad[n]) extra = 1;
}

int main() {
	scanf("%d%d", &N, &K);
	assert(N <= 100);
	for (int i = 1, A, B; i < N; i++) {
		scanf("%d%d", &A, &B);
		adj[A].push_back(B);
		adj[B].push_back(A);
	}
	for (int i = 1; i <= N; i++) {
		scanf("%d", &S[i]);
		tot[S[i]]++;
	}
	dfs(1, 0);
	for (int i = 1; i <= N; i++) D("%d", bad[i]);
	D("\n");
	dfs2(1, 0, 0);
	printf("%d\n", (ans+extra+1)/2);
}

Compilation message (stderr)

mergers.cpp: In function 'int main()':
mergers.cpp:57:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &N, &K);
  ~~~~~^~~~~~~~~~~~~~~~
mergers.cpp:60:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &A, &B);
   ~~~~~^~~~~~~~~~~~~~~~
mergers.cpp:65:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &S[i]);
   ~~~~~^~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 24
• Subtask 3: 0 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30