/// In The Name Of God
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
#define f first
#define s second
#define pb push_back
#define pp pop_back
#define mp make_pair
#define sz(x) (int)x.size()
#define sqr(x) ((x) * 1ll * (x))
#define all(x) x.begin(), x.end()
#define Kazakhstan ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define nl '\n'
#define ioi exit(0);
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
const int N = (int)1e6 + 7;
const int inf = (int)1e9 + 7;
const int mod = (int)1e9 + 7;
const ll linf = (ll)1e18 + 7;
const int dx[] = {-1, 0, 1, 0, 1, -1, -1, 1};
const int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
using namespace std;
int n, t, m;
struct solve {
int sz[N];
vector <int> g[N];
void dfs(int v = m, int p = -1) {
sz[v] = 1;
for (auto to : g[v]) {
if (to == p) continue;
dfs(to, v);
sz[v] += sz[to];
}
}
int calc(int v = m, int p = t) {
int mx = -1, cnt = 0;
for (auto to : g[v]) {
if (to == p) continue;
++cnt;
if (mx == -1 || sz[to] > sz[mx]) mx = to;
}
int go = -1;
for (auto to : g[v]) {
if (to == p || to == mx) continue;
if (go == -1 || sz[to] > sz[go]) go = to;
}
int res = cnt;
if (cnt > 1) res--;
if (go != -1) res += min(2, calc(go, v) + 2);
return res;
}
void prep() {
memset(sz, 0, sizeof(sz));
for (int i = 1; i <= n; i++) g[i].clear();
}
bool check() {
for (auto to : g[m]) {
if (to == t) return 1;
}
return 0;
}
int get() {
#ifdef IOI2018
freopen ("in.txt", "r", stdin);
#endif
Kazakhstan
cin >> n >> t >> m;
if (m == t) {
assert(0);
cout << 0, ioi
}
prep();
for (int i = 1; i < n; i++) {
int v, u;
cin >> v >> u;
g[v].pb(u);
g[u].pb(v);
}
if (!check()) {
cerr << "Incorrect test";
ioi
}
dfs();
return calc();
}
};
auto it = solve();
int get(int x) {
return rand() % x + 1;
}
vector <int> g[N];
void gen() {
int n = get(7);
if (n == 1) n++;
for (int i = 1; i <= n; i++) g[i].clear();
for (int i = 2; i <= n; i++) {
int p = get(i - 1);
g[p].pb(i);
g[i].pb(p);
}
ofstream out ("in.txt");
out << n << ' ';
while (1) {
int t = get(n);
if (!sz(g[t])) continue;
int p = get(sz(g[t]));
out << t << ' ' << g[t][p - 1] << nl;
//cerr << n << ' ' << t << ' ' << g[t][p - 1] << nl;
break;
}
for (int i = 1; i <= n; i++) {
for (auto to : g[i]) {
if (i < to) {
out << i << ' ' << to << nl;
//cerr << i << ' ' << to << nl;
}
}
}
out.close();
}
int main() {
cout << it.get();
ioi
while (1) {
int seed = time(0);
srand(seed);
for (int i = 1; i <= 100; i++) {
gen();
if (it.get() > 4) {
cerr << "seed -> " << seed << " " << "test -> " << i << endl;
cerr << it.get();
ioi
}
}
}
ioi
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
50 ms |
51192 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
50 ms |
51192 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
50 ms |
51192 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
