#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
#define pb push_back
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define lb lower_bound
#define ub upper_bound
using pi = pair<int,int>;
#define f first
#define s second
#define mp make_pair
namespace output {
void pr(int x) {
cout << x;
}
void pr(long x) {
cout << x;
}
void pr(ll x) {
cout << x;
}
void pr(unsigned x) {
cout << x;
}
void pr(unsigned long x) {
cout << x;
}
void pr(unsigned long long x) {
cout << x;
}
void pr(float x) {
cout << x;
}
void pr(double x) {
cout << x;
}
void pr(long double x) {
cout << x;
}
void pr(char x) {
cout << x;
}
void pr(const char * x) {
cout << x;
}
void pr(const string & x) {
cout << x;
}
void pr(bool x) {
pr(x ? "true" : "false");
}
template < class T1, class T2 > void pr(const pair < T1, T2 > & x);
template < class T > void pr(const T & x);
template < class T, class...Ts > void pr(const T & t,
const Ts & ...ts) {
pr(t);
pr(ts...);
}
template < class T1, class T2 > void pr(const pair < T1, T2 > & x) {
pr("{", x.f, ", ", x.s, "}");
}
template < class T > void pr(const T & x) {
pr("{"); // const iterator needed for vector<bool>
bool fst = 1;
for (const auto & a: x) pr(!fst ? ", " : "", a), fst = 0;
pr("}");
}
void ps() {
pr("\n");
} // print w/ spaces
template < class T, class...Ts > void ps(const T & t,
const Ts & ...ts) {
pr(t);
if (sizeof...(ts)) pr(" ");
ps(ts...);
}
void pc() {
cout << "]" << endl;
} // debug w/ commas
template < class T, class...Ts > void pc(const T & t,
const Ts & ...ts) {
pr(t);
if (sizeof...(ts)) pr(", ");
pc(ts...);
}
#define dbg(x...) pr("[", #x, "] = ["), pc(x);
}
#ifdef mikey
using namespace output;
#else
using namespace output;
#define dbg(x...)
#endif
const int MX = 1000005;
const int MOD = (int) (1e9 + 7);
const ll INF = (ll) 1e18;
struct fr{
ll x, y;
fr(ll X = 0, ll Y = 1){
x = X, y = Y;
ll g = __gcd(x, y);
x /= g, y /= g;
}
friend fr operator+(fr a, fr b){
return fr(a.x * b.y + b.x * a.y, a.y * b.y);
}
friend fr operator-(fr a, fr b){
return fr(a.x * b.y - b.x * a.y, a.y * b.y);
}
friend fr operator*(fr a, fr b){
return fr(a.x * b.x, a.y * b.y);
}
friend fr operator/(fr a, fr b){
return fr(a.x * b.y, a.y * b.x);
}
friend bool operator<(fr a, fr b){
return a.x * b.y < b.x * a.y;
}
};
int dat[MX];
vi adj[MX];
ll dp[MX], dp2[MX];
int anc[MX];
void dfs(int v, int p) {
if (dat[v] == 1) dp[v] = 1;
for (int to : adj[v]) {
if (to == p) continue;
anc[to] = v;
dfs(to, v);
if (dp[to] + (dat[v] == 1) > dp[v]) {
dp[v] = dp[to] + (dat[v] == 1);
}
}
if (dat[v] > 1) dp[v] = 0;
}
int main(){
#ifdef mikey
freopen("a.in", "r", stdin);
#endif
ios::sync_with_stdio(false);
cin.tie(0);
int n; cin >> n;
for (int i = 0; i < n - 1; i++) {
int u, v; cin >> u >> v;
u--, v--;
adj[u].pb(v), adj[v].pb(u);
}
memset(anc, -1, sizeof(anc));
for (int i = 0; i < n; i++) {
cin >> dat[i];
}
dfs(0, -1);
queue<int> bfs;
fr ans = fr(INF);
bfs.push(0);
while (!bfs.empty()) {
int curr = bfs.front();
bfs.pop();
for (int to : adj[curr]) {
if (to != anc[curr]) bfs.push(to);
}
if (anc[curr] != -1) {
if (dat[anc[curr]] == 1) {
dp2[curr] = dp2[anc[curr]] + 1;
for (int to : adj[anc[curr]]) {
if (to != curr && to != anc[anc[curr]]) {
dp2[curr] = max(dp2[curr], dp[to] + 1);
}
}
} else {
dp2[curr] = 0;
}
}
// dbg(curr, dp[curr], dp2[curr]);
if (dat[curr] > 1) {
ll best = dp2[curr], sbest = 0;
for (int to : adj[curr]) {
if (to != anc[curr]) {
if (dp[to] > best) {
sbest = best, best = dp[to];
} else if (dp[to] > sbest) {
sbest = dp[to];
}
}
}
fr ret = {dat[curr], best + sbest + 1};
if (ret < ans) ans = ret;
}
}
cout << ans.x << "/" << ans.y << '\n';
}
Compilation message
mag.cpp:104: warning: "dbg" redefined
104 | #define dbg(x...)
|
mag.cpp:97: note: this is the location of the previous definition
97 | #define dbg(x...) pr("[", #x, "] = ["), pc(x);
|
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
19 ms |
27756 KB |
Output is correct |
| 2 |
Incorrect |
20 ms |
27756 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
21 ms |
27884 KB |
Output is correct |
| 2 |
Correct |
19 ms |
27756 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
384 ms |
113644 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
19 ms |
27884 KB |
Output is correct |
| 2 |
Incorrect |
491 ms |
171116 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
466 ms |
167420 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
464 ms |
93548 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
403 ms |
98140 KB |
Output is correct |
| 2 |
Incorrect |
110 ms |
34540 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
123 ms |
33004 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
393 ms |
91236 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
444 ms |
91480 KB |
Output is correct |
| 2 |
Incorrect |
422 ms |
61676 KB |
Output isn't correct |
