// g++ -std=c++14
/*
Today might be the chance to grasp the chance to let your talent bloom.
May be tomorrow, the day after, or next year...
May be even when you are 30. I'm not sure if physique has anything to do with it
but if you think that it will never come, it probably never will.
- Tooru Oikawa.
*/
#include<bits/stdc++.h>
typedef long long ll;
typedef long double lld;
using namespace std;
#define endl "\n"
#define fi first
#define se second
#define pb(x) push_back(x)
#define mp(x,y) make_pair(x,y)
#define MEMS(a,b) memset(a,b,sizeof(a))
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define __ freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);
#define all(c) c.begin(),c.end()
#define pii pair<int, int>
#define tr(...) cout<<__FUNCTION__<<' '<<__LINE__<<" = ";trace(#__VA_ARGS__, __VA_ARGS__)
template<typename S, typename T>
ostream& operator<<(ostream& out,pair<S,T> const& p){out<<'('<<p.fi<<", "<<p.se<<')';return out;}
template<typename T>
ostream& operator<<(ostream& out,vector<T> const& v){
ll l=v.size();for(ll i=0;i<l-1;i++)out<<v[i]<<' ';if(l>0)out<<v[l-1];return out;}
template <typename T>
ostream &operator<<(ostream &out, set<T> const &v) {
for (auto i = v.begin(); i != v.end(); i++)
out << (*i) << ' ';
return out;
}
template <typename T, typename V>
ostream &operator<<(ostream &out, map<T, V> const &v) {
for (auto i = v.begin(); i != v.end(); i++)
out << "\n" << (i->first) << ":" << (i->second);
return out;
}
template<typename T>
void trace(const char* name, T&& arg1){cout<<name<<" : "<<arg1<<endl;}
template<typename T, typename... Args>
void trace(const char* names, T&& arg1, Args&&... args){
const char* comma = strchr(names + 1, ',');cout.write(names, comma-names)<<" : "<<arg1<<" | ";trace(comma+1,args...);}
#define int ll
const int N = 1e6 + 100;
int n;
vector<vector<int>> g(N);
int arr[N];
int dp_down[N], dp_up[N];
int parent[N];
int ans0 = 0;
void dfs0(int v, int p) {
parent[v] = p;
int curr = (arr[v] == 1);
vector<int> child;
for (auto u : g[v]) {
if (u == p) continue;
dfs0(u, v);
curr = max(curr, dp_down[u] + 1);
child.push_back(dp_down[u]);
}
if (arr[v] == 1) {
dp_down[v] = curr;
if (child.empty()) {
ans0 = max(ans0, 1LL);
} else if ((int)child.size() == 1) {
ans0 = max(ans0, child.back() + 1);
} else {
sort(all(child));
reverse(all(child));
ans0 = max(ans0, child[0] + child[1] + 1LL);
}
}
}
void dfs1(int v, int p, int mx_len = 0) {
// tr(v, mx_len);
dp_up[v] = mx_len;
if (arr[v] == 1) {
multiset<int> child;
child.insert(mx_len);
for (auto u : g[v]) {
if (u == p) continue;
child.insert(dp_down[u]);
}
for (auto u : g[v]) {
if (u == p) continue;
child.erase(child.find(dp_down[u]));
int heremx = *child.rbegin() + 1;
dfs1(u, v, heremx);
child.insert(dp_down[u]);
}
} else {
for (auto u : g[v]) {
if (u == p) continue;
dfs1(u, v, 0);
}
}
}
int cmp(int a, int b, int c, int d) {
return (a * d < c * b);
}
const int inf = 1e18 + 1;
int solve() {
cin >> n;
for (int i = 0; i < n - 1; i++) {
int v, u;
cin >> v >> u;
g[u].push_back(v);
g[v].push_back(u);
}
for (int i = 1; i <= n; i++) {
cin >> arr[i];
}
dfs0(1, 0);
dfs1(1, 0);
if (ans0 == 0) {
int mi = inf;
for (int i = 1; i <= n; i++) {
mi = min(mi, arr[i]);
}
cout << mi << "/1" << endl;
} else {
int a = 1, b = ans0;
for (int i = 1; i <= n; i++) {
vector<int> pth;
for (auto j : g[i]) {
if (j == parent[i]) continue;
pth.push_back(dp_down[j]);
}
pth.push_back(dp_up[i]);
sort(all(pth));
reverse(all(pth));
// tr(i, pth, a, b);
if ((int)pth.size() == 1) {
int c = arr[i], d = pth[0] + 1;
if (!cmp(a, b, c, d)) {
a = c, b = d;
}
} else {
int c = arr[i], d = 1 + pth[0] + pth[1];
if (!cmp(a, b, c, d)) {
a = c, b = d;
}
}
}
int g = __gcd(a, b);
a /= g;
b /= g;
cout << a << "/" << b << endl;
}
return 0;
}
int32_t main(){ _
int t;
// cin >> t;
t = 1;
while (t--) solve();
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
20 ms |
23936 KB |
Output is correct |
| 2 |
Correct |
18 ms |
23936 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
18 ms |
23936 KB |
Output is correct |
| 2 |
Correct |
20 ms |
24064 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
691 ms |
149112 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
18 ms |
23936 KB |
Output is correct |
| 2 |
Correct |
813 ms |
250876 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
760 ms |
262148 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
733 ms |
86136 KB |
Output is correct |
| 2 |
Correct |
505 ms |
70268 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
590 ms |
95160 KB |
Output is correct |
| 2 |
Correct |
167 ms |
30712 KB |
Output is correct |
| 3 |
Runtime error |
719 ms |
262148 KB |
Execution killed with signal 9 (could be triggered by violating memory limits) |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
137 ms |
30772 KB |
Output is correct |
| 2 |
Correct |
714 ms |
87928 KB |
Output is correct |
| 3 |
Correct |
617 ms |
58360 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
620 ms |
85120 KB |
Output is correct |
| 2 |
Correct |
690 ms |
85540 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
716 ms |
88056 KB |
Output is correct |
| 2 |
Correct |
672 ms |
58236 KB |
Output is correct |
