제출 #398190

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
398190		ChrisT	Meetings 2 (JOI21_meetings2)	C++17	100 / 100	1079 ms	24324 KiB

meetings2

#include <bits/stdc++.h>
using namespace std;
const int MN = 2e5 + 5;
vector<int> adj[MN];
bool vis[MN];
int sz[MN], ans[MN], bit[MN], cent; vector<array<int,2>> toadd;
void update (int i, int v) {
	for (i=MN-i;i<MN;i+=i&-i)
		bit[i] = max(bit[i],v);
}
int query (int i) {
	int ret = -1e9;
	for (i=MN-i;i;i^=i&-i)
		ret = max(ret,bit[i]);
	return ret;
}
void clear (int i) {
	for (i=MN-i;i;i^=i&-i)
		bit[i] = 0;
}
void getsz (int cur, int p = -1) {
	sz[cur] = 1;
	for (int i : adj[cur]) if (!vis[i] && i != p) {
		getsz(i,cur);
		sz[cur] += sz[i];
	}
}
int getcent (int cur, int tot, int p = -1) {
	for (int i : adj[cur]) if (!vis[i] && i != p && sz[i] > tot/2)
		return getcent(i,tot,cur);
	return cur;
}
void dfs (int cur, int ch, int depth = 1, int p = -1) {
	toadd.push_back({sz[cur],depth});
	ans[sz[cur]*2] = max(ans[sz[cur]*2],depth + query(sz[cur]) + 1);
	if (sz[cent] - sz[ch] >= sz[cur]) ans[sz[cur]*2] = max(ans[sz[cur]*2],depth + 1);
	for (int i : adj[cur]) if (i != p && !vis[i]) {
		dfs(i,ch,depth+1,cur);
	}
}
void decomp (int cur) {
	getsz(cur);
	cent = getcent(cur,sz[cur]);
	vis[cent] = 1; getsz(cent);
	for (int i : adj[cent]) if (!vis[i]) {
		dfs(i,i);
		for (auto &[s,d] : toadd) update(s,d);
		toadd.clear();
	}
	for (int i = 1; i <= sz[cent]; i++) clear(i);
	reverse(adj[cent].begin(),adj[cent].end());
	for (int i : adj[cent]) if (!vis[i]) {
		dfs(i,i);
		for (auto &[s,d] : toadd) update(s,d);
		toadd.clear();
	}
	for (int i = 1; i <= sz[cent]; i++) clear(i);
	for (int i : adj[cent]) if (!vis[i]) decomp(i);
}
int main () {
	int n; scanf ("%d",&n);
	for (int i = 1; i < n; i++) {
		int a,b; scanf ("%d %d",&a,&b);
		adj[a].push_back(b); adj[b].push_back(a);
	}
	decomp(1);
	for (int i = n - (n%2); i > 2; i -= 2) ans[i-2] = max(ans[i-2],ans[i]);
	for (int i = 1; i <= n; i++) printf ("%d\n",i&1?1:max(1,ans[i]));
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

meetings2.cpp: In function 'int main()':
meetings2.cpp:61:15: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   61 |  int n; scanf ("%d",&n);
      |         ~~~~~~^~~~~~~~~
meetings2.cpp:63:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   63 |   int a,b; scanf ("%d %d",&a,&b);
      |            ~~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 16 / 16
• Subtask 3: 80 / 80