cf1088E Ehab and a component choosing problem (树形dp)

 1 #include<bits/stdc++.h>
 2 #define pa pair<int,int>
 3 #define CLR(a,x) memset(a,x,sizeof(a))
 4 #define MP make_pair
 5 using namespace std;
 6 typedef long long ll;
 7 const int maxn=3e5+10;
 8 
 9 inline char gc(){
10     return getchar();
11     static const int maxs=1<<16;static char buf[maxs],*p1=buf,*p2=buf;
12     return p1==p2&&(p2=(p1=buf)+fread(buf,1,maxs,stdin),p1==p2)?EOF:*p1++;
13 }
14 inline ll rd(){
15     ll x=0;char c=gc();bool neg=0;
16     while(c<‘0‘||c>‘9‘){if(c==‘-‘) neg=1;c=gc();}
17     while(c>=‘0‘&&c<=‘9‘) x=(x<<1)+(x<<3)+c-‘0‘,c=gc();
18     return neg?(~x+1):x;
19 }
20 
21 int N,a[maxn];
22 int eg[maxn*2][2],egh[maxn],ect;
23 ll f[maxn],answ=-1e15,ansk;
24 
25 inline void adeg(int a,int b){
26     eg[++ect][0]=b,eg[ect][1]=egh[a],egh[a]=ect;
27 }
28 
29 inline void dfs1(int x,int fa){
30     f[x]=a[x];
31     for(int i=egh[x];i;i=eg[i][1]){
32         int b=eg[i][0];if(b==fa) continue;
33         dfs1(b,x);
34         if(f[b]>0) f[x]+=f[b];
35     }
36     answ=max(answ,f[x]);
37 }
38 inline void dfs2(int x,int fa){
39     f[x]=a[x];
40     for(int i=egh[x];i;i=eg[i][1]){
41         int b=eg[i][0];if(b==fa) continue;
42         dfs2(b,x);
43         if(f[b]>0) f[x]+=f[b];
44     }
45     if(f[x]==answ) ansk++,f[x]=-1e15;
46 }
47 
48 int main(){
49     //freopen("","r",stdin);
50     int i,j,k;
51     N=rd();
52     for(i=1;i<=N;i++) a[i]=rd();
53     for(i=1;i<N;i++){
54         int a=rd(),b=rd();
55         adeg(a,b);adeg(b,a);
56     }
57     dfs1(1,0);dfs2(1,0);
58     answ*=ansk;
59     printf("%I64d %I64d\n",answ,ansk);
60     return 0;
61 }