#pragma GCC optimize("Ofast,unroll-loops")
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma,tune=native")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef int ll;
typedef long double ld;
typedef pair <ll, ll> pll;
#ifdef SINA
#define dbg(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1> void __f(const char* name, Arg1&& arg1) { cout << name << " : " << arg1 << std::endl; }
template <typename Arg1, typename... Args> void __f (const char* names, Arg1&& arg1, Args&&... args) {
const char* comma = strchr(names + 1, ',');cout.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...); }
#define dbg2(x, j, n) cout<< #x << " : "; output((j), (n), x, 1); cout.flush();
#else
#define dbg(...) 0
#define dbg2(x, j, n) 0
#endif
#define SZ(x) ((ll)((x).size()))
#define File(s, t) freopen(s ".txt", "r", stdin); freopen(t ".txt", "w", stdout);
#define input(j, n, a) for (int _i = (j); _i < (n)+(j); _i++) cin>> a[_i];
#define output(j, n, a, t) for (int _i = (j); _i < (n)+(j); _i++) cout<< a[_i] << (((t) && _i != (n)+(j)-1)? ' ' : '\n');
#define kill(x) return cout<< (x) << endl, 0
#define cl const ll
#define fr first
#define sc second
#define lc (v << 1)
#define rc (lc | 1)
#define mid ((l + r) >> 1)
#define All(x) (x).begin(), (x).end()
cl inf = sizeof(ll) == 4 ? (1e9 + 10) : (3e18), mod = 1e9 + 7, MOD = 998244353;
template <class A,class B> ostream& operator << (ostream& out,const pair<A,B>&a){return out<<'('<<a.first<<", "<<a.second<<')';}
template <class A> ostream& operator << (ostream& out, const vector<A> &a) {
out<< '['; for (int i = -1; ++i < int(a.size());) out<< a[i] << (i + 1 < int(a.size()) ? ", " : ""); return out<<']'; }
template <class T, typename _t = less <T> > using Tree = tree <T, null_type, _t, rb_tree_tag, tree_order_statistics_node_update>;
cl N = 1e6 + 7;
ll par [N], n, t, m;
vector <ll> adj [N], path, dps [N];
bool mark [N];
void dfst (cl &v = t, cl &pr = -1) {
par[v] = pr;
for (auto &u : adj[v]) if (u != pr) dfst(u, v);
}
ll dfs (cl &v, cl &pr) {
vector <ll> vals = {0, 0};
for (auto &u : adj[v]) if (u != pr) vals.push_back(dfs(u, v));
sort(All(vals));
return vals[SZ(vals) - 2] + SZ(adj[v]) - 1;
}
bool check (ll x) {
ll c = 1;
for (ll i = 0; i < SZ(path) - 1; i++) {
ll rm = SZ(dps[i]);
for (auto &y : dps[i]) {
if(y + rm > x) {
rm--;
c--;
x--;
}
}
if (c < 0) return false;
c++;
}
return (x >= 0);
}
int main ()
{
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin>> n >> t >> m;
for (ll i = 1, v, u; i < n; i++) {
cin>> v >> u;
adj[v].push_back(u);
adj[u].push_back(v);
}
dfst();
for (ll i = m; i != -1; i = par[i]) path.push_back(i), mark[i] = 1;
for (ll i = 0, v; i < SZ(path) - 1; i++) {
v = path[i];
for (auto &u : adj[v]) if (!mark[u]) dps[i].push_back(dfs(u, v));
}
for (ll i = SZ(path) - 2, tot = 0; i >= 0; i--) {
for (auto &x : dps[i]) x += tot;
sort(All(dps[i]), greater <ll> ());
tot += SZ(adj[path[i]]) - 2;
}
ll l = 0, r = N + N;
while (r - l > 1) {
if (check(mid)) r = mid;
else l = mid;
}
kill(r);
cerr<< "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
return 0;
}
/*
10 1 4
1 2
2 3
2 4
3 9
3 5
4 7
4 6
6 8
7 10
*/
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
39 ms |
47172 KB |
Output is correct |
| 2 |
Correct |
32 ms |
47204 KB |
Output is correct |
| 3 |
Incorrect |
32 ms |
47192 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
430 ms |
95948 KB |
Output is correct |
| 2 |
Correct |
395 ms |
90960 KB |
Output is correct |
| 3 |
Correct |
1107 ms |
96892 KB |
Output is correct |
| 4 |
Correct |
571 ms |
71924 KB |
Output is correct |
| 5 |
Correct |
1094 ms |
96708 KB |
Output is correct |
| 6 |
Correct |
1118 ms |
96808 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
39 ms |
47172 KB |
Output is correct |
| 2 |
Correct |
32 ms |
47204 KB |
Output is correct |
| 3 |
Incorrect |
32 ms |
47192 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
39 ms |
47172 KB |
Output is correct |
| 2 |
Correct |
32 ms |
47204 KB |
Output is correct |
| 3 |
Incorrect |
32 ms |
47192 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
