BZOJ3573: [Hnoi2014]米特运输

题目：http://www.lydsy.com/JudgeOnline/problem.php?id=3573

如果一个点的权值确定了，那么这棵树就确定了，我们对每一个点统计根节点是它的多少倍（太大于是开了log），然后找下众数就可以了。

 
#include<cstring>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<queue>
#define rep(i,l,r) for (int i=l;i<=r;i++)
#define down(i,l,r) for (int i=l;i>=r;i--)
#define clr(x,y) memset(x,y,sizeof(x))
#define maxn 500500
#define inf int(1e9)
#define eps 1e-6
using namespace std;
struct data{int obj,pre;
}e[maxn*2];
double s[maxn];
int a[maxn],n,tot,head[maxn],d[maxn];
void insert(int x,int y){
    e[++tot].obj=y; e[tot].pre=head[x]; head[x]=tot;
}
int read(){
    int x=0,f=1;  char ch=getchar();
    while (!isdigit(ch)) {
        if (ch=='-') f=-1; ch=getchar();
    }
    while (isdigit(ch)){
        x=x*10+ch-'0'; ch=getchar();
    }
    return x*f;
}
void dfs(int u,int fa){
    for (int j=head[u];j;j=e[j].pre){
        int v=e[j].obj;
        double now=(double)log(d[u]);
        if (v!=fa){
            s[v]=s[u]+now;
            dfs(v,u);
        }
    }
}
int main(){
    n=read();
    rep(i,1,n) a[i]=read();
    rep(i,1,n-1){
        int x=read(),y=read();
        insert(x,y); insert(y,x);
        d[x]++; d[y]++;
    }
    s[1]=log(1);
    rep(i,2,n) d[i]--;
    dfs(1,0);
    rep(i,1,n) s[i]=s[i]+(double)log(a[i]);
    sort(s+1,s+1+n);
    int tmp=1,ans=0;
    rep(i,2,n){
        if (fabs(s[i]-s[i-1])<=eps) tmp++;
        else ans=max(ans,tmp),tmp=1;
    }
    ans=max(ans,tmp);
    printf("%d\n",n-ans);
    return 0;
}