BZOJ 3727 Final Zadanie

递推一下什么的就好了。。。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxv 300050
#define maxe 600050
using namespace std;
long long n,x,y,g[maxv],nume=1,tot1=0,tot2=0,dis[maxv],b[maxv],sum[maxv];
long long fath[maxv];
struct edge
{
    long long v,nxt;
}e[maxe];
void addedge(long long u,long long v)
{
    e[++nume].v=v;e[nume].nxt=g[u];
    g[u]=nume;
}
long long read()
{
    char ch;long long data=0;
    while (ch<'0' || ch>'9') ch=getchar();
    while (ch>='0' && ch<='9')
    {
        data=data*10+ch-'0';
        ch=getchar();
    }
    return data;
}
void dfs1(long long x)
{
    if (x-1) tot2+=(b[fath[x]]-b[x]);
    for (long long i=g[x];i;i=e[i].nxt)
    {
        long long v=e[i].v;
        if (v!=fath[x])
        {
            fath[v]=x;dis[v]=dis[x]+1;
            dfs1(v);
        }
    }
}
void dfs2(long long x)
{
    for (long long i=g[x];i;i=e[i].nxt)
    {
        long long v=e[i].v;
        if (v!=fath[x]) {sum[x]-=sum[v];dfs2(v);}
    }
}
int main()
{
    n=read();
    for (long long i=1;i<=n-1;i++)
    {
        x=read();y=read();
        addedge(x,y);addedge(y,x);
    }
    for (int i=1;i<=n;i++) scanf("%lld",&b[i]);
    dfs1(1);
    sum[1]=(2*b[1]-tot2)/(n-1);for (long long i=2;i<=n;i++) sum[i]=(sum[1]+b[fath[i]]-b[i])/2;
    dfs2(1);
    for (long long i=1;i<=n-1;i++) printf("%lld ",sum[i]);
    printf("%lld\n",sum[n]);
    return 0;
}