cf 543 D. Road Improvement

（懒得想了，，又是DP）

#include<bits/stdc++.h>
#define N 200005
#define LL long long
#define inf 0x3f3f3f3f
#define ls tr[x][0]
#define rs tr[x][1]
using namespace std;
inline int ra()
{
    int x=0,f=1; char ch=getchar();
    while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
    while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
    return x*f;
}
const int mod=1e9+7;
vector<LL > G[N],L[N],R[N];
LL dp[N],up[N];
int n;
void dfsdown(int x, int fa)
{
    dp[x]=1;
    for (int i=0; i<G[x].size(); i++)
    {
        int v=G[x][i];
        if (v==fa) {L[x].push_back(1); R[x].push_back(1); continue;}
        dfsdown(v,x);
        L[x].push_back(dp[v]+1);
        R[x].push_back(dp[v]+1);
        dp[x]=dp[x]*(dp[v]+1)%mod;
    }
    for (int i=1; i<L[x].size(); i++) L[x][i]=L[x][i]*L[x][i-1]%mod;
    for (int i=R[x].size()-2;i>=0; i--) R[x][i]=R[x][i]*R[x][i+1]%mod;
}
void dfsup(int x, int fa, int val)
{
    up[x]=val; LL tem;
    for (int i=0; i<G[x].size(); i++)
    {
        int v=G[x][i];
        tem=val;
        if (v==fa) continue;
        if (i>0) tem=tem*L[x][i-1]%mod;
        if (i<G[x].size()-1) tem=tem*R[x][i+1]%mod;
        dfsup(v,x,tem+1);
    }
}
int main()
{
    n=ra();
    for (int i=2; i<=n; i++)
    {
        int x=ra();
        G[x].push_back(i); 
        G[i].push_back(x);
    }
    dfsdown(1,0); dfsup(1,0,1);
    for (int i=1; i<=n; i++)
        printf("%I64d ",up[i]*dp[i]%mod);
}