BZOJ 5072: [Lydsy十月月赛]小A的树 树形dp

...懒...

#include<cmath>
#include<ctime>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<iomanip>
#include<vector>
#include<string>
#include<bitset>
#include<queue>
#include<map>
#include<set>
using namespace std;

inline int read()
{
	int x=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch<='9'&&ch>='0'){x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}
	return x*f;
}
void print(int x)
{if(x<0)putchar('-'),x=-x;if(x>=10)print(x/10);putchar(x%10+'0');}

const int N=5010;

int last[N],ecnt;
struct EDGE{int to,nt;}e[N<<1];
inline void add(int u,int v)
{e[++ecnt]=(EDGE){v,last[u]};last[u]=ecnt;}

int size[N],fa[N];

int V[N],f[N][N],g[N][N],ff[N],gg[N],sf[N],sg[N];

void dfs(int u)
{
	size[u]=1;
	f[u][1]=g[u][1]=V[u];
	for(int i=last[u];i;i=e[i].nt)
		if(fa[u]^e[i].to)
		{
			fa[e[i].to]=u;
			dfs(e[i].to);
			memcpy(ff,f[u],sizeof(ff));
			memcpy(gg,g[u],sizeof(gg));
			for(int j=1;j<=size[u];++j)for(int k=1;k<=size[e[i].to];++k)
				ff[j+k]=max(ff[j+k],f[u][j]+f[e[i].to][k]),
				gg[j+k]=min(gg[j+k],g[u][j]+g[e[i].to][k]);
			size[u]+=size[e[i].to];
			for(int j=1;j<=size[u];++j)f[u][j]=ff[j],g[u][j]=gg[j];
		}
	for(int i=1;i<=size[u];++i)
		sf[i]=max(sf[i],f[u][i]),sg[i]=min(sg[i],g[u][i]);
}

void initial()
{
	ecnt=0;
	memset(last,0,sizeof(last));
	memset(f,0,sizeof(f));
	memset(g,0X3f,sizeof(g));
	memset(sf,0,sizeof(sf));
	memset(sg,0X3f,sizeof(sg));
}

int main()
{
	int T=read();
	while(T--)
	{
		initial();
		int n=read();int Q=read();
		for(int u,v,i=1;i<n;++i)
		{
			u=read();v=read();
			add(u,v);add(v,u);
		}
		for(int i=1;i<=n;++i)V[i]=read();
		dfs(1);
		while(Q--)
		{
			int x=read(),y=read();
			if(y<=sf[x]&&y>=sg[x])puts("YES");
			else puts("NO");
		}
		puts("");
	}
	return 0;
}
/*
1
9 4
4 1
1 5
1 2
3 2
3 6
6 7
6 8
9 6
0 1 0 1 0 0 1 0 1
3 2
7 3
4 0
9 5

YES
YES
NO
NO
*/