#include<bits/stdc++.h>
using namespace std;
//#include<ext/pb_ds/assoc_container.hpp>
//#include<ext/pb_ds/tree_policy.hpp>
//
// #pragma GCC optimize("unroll-loops")
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("-O3")
// #pragma GCC optimize("no-stack-protector")
// #pragma GCC optimize("fast-math")
//#define LOCAL
#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cout<< *x, 0);
sim > char dud(...);
struct debug {
#ifndef LOCAL
~debug() { cout << endl; }
eni(!=) cout << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
*this << "[";
for (auto it = d.b; it != d.e; ++it)
*this << ", " + 2 * (it == d.b) << *it;
ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define fi first
#define f first
#define se second
#define s second
#define vi_a vector<int>a;
#define p_b push_back
////////////////////////////////???????????????CHECK THIS OUT???????????????//////////////////////////////
#define ll long long
////////////////////////////////???????????????CHECK THIS OUT???????????????//////////////////////////////
#define ld long double
#define pll pair<ll,ll>
#define pii pair<int,int>
#define m_p make_pair
#define fast_io cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);
#define all(x) x.begin(),x.end()
#define getfiles ifstream cin("input.txt");ofstream cout("output.txt");
#define pw(x) (1ll << x)
#define sz(x) (ll)x.size()
#define endl "\n"
#define rall(x) x.rbegin(),x.rend()
#define len(a) (ll)a.size()
#define rep(x,l,r) for(ll x=l;x<r;x++)
//using namespace __gnu_pbds;
ld eps = (ld)1 / 1e6;
const ld pi=3.14159265359;
ll inf = 1e18,mod1=1e9+7;
ll sqr(ll a) { return a * a; }
ll qb(ll a) { return a * a * a; }
ll gcd(ll a, ll b) { return !a ? b : gcd(b % a, a); }
ll binpow(ll a, ll b, ll mod) { return b ? (b % 2 ? (a * (sqr(binpow(a, b / 2, mod)) % mod)) % mod : sqr(binpow(a, b / 2, mod)) % mod) : 1; }
ll binmult(ll a, ll b, ll mod) { return b ? (b % 2 ? (2 * binmult(a, b / 2, mod) + a) % mod : (2 * binmult(a, b / 2, mod)) % mod) : 0; }
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const ll R=1e4;
const ll tx[4]={0,0,-1,1};
const ll ty[4]={-1,1,0,0};
const char rev_to[4]={'E','W','N','S'};
const int N=2e6+1;
const int M=999999937;
ll a[N];
int n,v,u;
pll ans={1e18,1};
ll f[N];
vector<int>g[N];
void dfs(int v,int p){
f[v]=a[v]==1;
for(auto &z :g[v]){
if(z^p){
dfs(z,v);
if(a[v]==1) f[v]=max(f[v],f[z]+1);
}
}
}
bool cmp(pll a,pll b){
ld l=(ld) a.f/a.s,r=(ld)b.f/b.s;
return r-l>0;
}
ll ff=0,s=0;
void dfs1(int v,int p,ll to){
// ans=min(ans,{a[v],1});
if(cmp({a[v],1},ans))ans={a[v],1};
ll mx=to;
// debug()<<imie(to)<<imie(v)<<imie(ans)<<imie(f[v]);
for(auto &z :g[v]){
if(z^p){
if(a[v]<=2){
if(cmp({a[v],1+mx+f[z]},ans)) ans={a[v],1+mx+f[z]};
// debug()<<imie(to)<<imie(v)<<imie(ans)<<imie(f[v]);
if(a[v]==1)ff=max(ff,mx+1+f[z]);
mx=max(mx,f[z]);
}
if(a[v]==2){
// cout<<"F"<<a[v]<<' '<<1+mx+f[z]<<endl;
s=max(s,mx+1+f[z]);
// cout.flush();
}
dfs1(z,v,(a[v]==1 ? to+1 : 0));
}
}
}
signed main(){
fast_io;
// freopen("5.in","r",stdin);
cin>>n;
for(int i=1;i<n;i++){
cin>>v>>u;--v;--u;
g[v].p_b(u);g[u].p_b(v);
}
for(int i=0;i<n;i++) cin>>a[i];
dfs(0,0);
dfs1(0,0,0);
if(ff && s){
if(2*ff<s){
ans={2,s};
}
else{
ans={1,ff};
}
}
ll gc=__gcd(ans.f,ans.s);
cout<<ans.f/gc<<'/'<<ans.s/gc;
return 0;
}
///stuff you should look for :
/*
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* read the conditions carefully
* WRITE STUFF DOWN
*/
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
33 ms |
47352 KB |
Output is correct |
| 2 |
Incorrect |
33 ms |
47356 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
33 ms |
47360 KB |
Output is correct |
| 2 |
Incorrect |
34 ms |
47352 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
406 ms |
118732 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
32 ms |
47360 KB |
Output is correct |
| 2 |
Incorrect |
529 ms |
173000 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
536 ms |
169468 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
449 ms |
94112 KB |
Output is correct |
| 2 |
Incorrect |
346 ms |
81732 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
452 ms |
95208 KB |
Output is correct |
| 2 |
Correct |
103 ms |
52088 KB |
Output is correct |
| 3 |
Correct |
537 ms |
172668 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
96 ms |
52088 KB |
Output is correct |
| 2 |
Correct |
457 ms |
94640 KB |
Output is correct |
| 3 |
Correct |
449 ms |
71520 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
437 ms |
91376 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
496 ms |
94716 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
