错的也敢发上来？ 代码：

//好像没什么可注释的...
#include<cstdio>
const int maxn=10005;
const int maxm=maxn<<1;
const int inf=0x3f3f3f3f;
int f[maxn][2];
int n,m,tot,x,y,root;
int c[maxn],h[maxn],to[maxm],nxt[maxm];
int min(int x,int y){
	return x<y?x:y;
}
void read(int&x){
	x=0;
	bool f=0;
	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&15);
		ch=getchar();
	}
	if(f)x=-x;
	return;
}
void add(int x,int y){
	to[++tot]=y;
	nxt[tot]=h[x];
	h[x]=tot;
	to[++tot]=x;
	nxt[tot]=h[y];
	h[y]=tot;
	return;
}
void dfs(int x,int fa){
	for(int i=h[x];i;i=nxt[i]){
		int e=to[i];
		if(e==fa)continue;
		dfs(e,x);
		f[x][0]+=min(f[e][0]-1,f[e][1]);
		f[x][1]+=min(f[e][0],f[e][1]-1);
	}
	return;
}
int main(){
	read(n);read(m);
	for(int i=1;i<=m;++i){
		read(c[i]);
		f[i][c[i]]=1;
		f[i][!c[i]]=inf;
	}
	for(int i=1;i<n;++i){
		read(x);read(y);
		add(x,y);
	}
	for(int i=m+1;i<=n;++i)
		f[i][0]=f[i][1]=1;
	dfs(n,-1);	//本来之前我也不知道可以随便选根，据说 n 当根可以过，我就用 n 做根了www
	printf("%d",min(f[n][0],f[n][1]));
	return 0;
}

#define MAXM 10010
#define INF 20000
using namespace std;
struct node
{
    int to, next;
} e[MAXM << 1];
int head[MAXM], tot;
int f[MAXM][3], m, n, c[MAXM];
void add(int u, int v)
{
    tot++, e[tot].to = v, e[tot].next = head[u], head[u] = tot;
}
void init()
{
    int i, u, v;
    scanf("%d%d", &m, &n);
    for (i = 1; i <= n; i++)
        scanf("%d", &c[i]);
    for (i = 1; i < m; i++)
    {
        scanf("%d%d", &u, &v);
        add(u, v), add(v, u);
    }
    for (i = 1; i <= m; i++)
        f[i][0] = f[i][1] = 1;
}
void dfs(int u, int fa)
{
    int i, v;
    for (i = head[u]; i; i = e[i].next)
    {
        v = e[i].to;
        if (v == fa)
            continue;
        dfs(v, u);
        if (v <= n)
            f[v][!c[v]] = INF, f[v][2] = 1;
        f[u][0] += min(f[v][2], min(f[v][0] - 1, f[v][1]));
        f[u][1] += min(f[v][2], min(f[v][0], f[v][1] - 1));
        f[u][2] += min(f[v][2], min(f[v][0], f[v][1]));
    }
}
int main()
{
    init();
    dfs(n + 1, -1);
    printf("%d\n", min(f[n + 1][2], min(f[n + 1][0], f[n + 1][1])));
    return 0;
}