제출 #1316190

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1316190		boclobanchat	Mergers (JOI19_mergers)	C++20	0 / 100	35 ms	15984 KiB

mergers

#include<bits/stdc++.h>
using namespace std;
const int MAXN=5e5+5;
const int INF=1e9;
int A[MAXN],sp[MAXN][20],dis[MAXN],F[MAXN],pre[MAXN],dp[MAXN][2];
vector<int> ds[MAXN];
void dfs(int i,int pre)
{
	sp[i][0]=pre;
	for(int j=1;j<=19;j++) sp[i][j]=sp[sp[i][j-1]][j-1];
	for(auto v:ds[i]) if(v!=pre)
	{
		dis[v]=dis[i]+1;
		dfs(v,i);
	}
}
int lca(int a,int b)
{
	int x=dis[a],y=dis[b],m=min(x,y);
	for(int i=19;i+1;i--)
	{
		if((x-m)&(1<<i)) a=sp[a][i];
		if((y-m)&(1<<i)) b=sp[b][i];
	}
	if(a==b) return a;
	for(int i=19;i+1;i--) if(sp[a][i]!=sp[b][i]) a=sp[a][i],b=sp[b][i];
}
void dfs2(int i,int pre)
{
	dp[i][0]=0,dp[i][1]=INF;
	for(auto v:ds[i]) if(v!=pre)
	{
		dfs2(v,i);
		F[i]+=F[v];
		int pa=dp[i][0],pb=dp[i][1];
		dp[i][0]=INF;
		dp[i][1]=min(pa,pb)+min(dp[v][0]+1,dp[v][1]);
		if(F[v])
		{
			dp[i][0]=min(dp[i][0],pa+min(dp[v][0],dp[v][1]));
			dp[i][1]=min(dp[i][1],pb+min(dp[v][0],dp[v][1]));
		}
	}
}
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,k;
	cin>>n>>k;
	for(int i=1;i<n;i++)
	{
		int l,r;
		cin>>l>>r;
		ds[l].push_back(r),ds[r].push_back(l);
	}
	dfs(1,1);
	for(int i=1;i<=n;i++)
	{
		cin>>A[i];
		if(pre[A[i]]) F[i]++,F[pre[A[i]]]++,F[lca(i,pre[A[i]])]-=2;
		pre[A[i]]=i;
	}
	dfs2(1,1);
	cout<<(min(dp[1][0],dp[1][1])+1)/2;
}

컴파일 시 표준 에러 (stderr) 메시지

mergers.cpp: In function 'int lca(int, int)':
mergers.cpp:27:1: warning: control reaches end of non-void function [-Wreturn-type]
   27 | }
      | ^

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