//thatsramen
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define eb emplace_back
#define pb push_back
#define ft first
#define sd second
#define pi pair<int, int>
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define dbg(...) dbg_out(__VA_ARGS__)
using ll = long long;
using ld = long double;
using namespace std;
using namespace __gnu_pbds;
//Constants
const ll INF = 5 * 1e18;
const int IINF = 2 * 1e9;
// const ll MOD = 1e9 + 7;
const ll MOD = 998244353;
const ll dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
const ld PI = 3.14159265359;
//Templates
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) {return os << '(' << p.first << ", " << p.second << ')';}
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) {os << '['; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << ']';}
void dbg_out() {cerr << endl;}
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << H << ' '; dbg_out(T...); }
template<typename T> void mins(T& x, T y) {x = min(x, y);}
template<typename T> void maxs(T& x, T y) {x = max(x, y);}
template<typename T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using omset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
//order_of_key(k): number of elements strictly less than k
//find_by_order(k): k-th element in the set
void setPrec() {cout << fixed << setprecision(15);}
void unsyncIO() {cin.tie(0)->sync_with_stdio(0);}
void setIn(string s) {freopen(s.c_str(), "r", stdin);}
void setOut(string s) {freopen(s.c_str(), "w", stdout);}
void setIO(string s = "") {
unsyncIO(); setPrec();
if(s.size()) setIn(s + ".in"), setOut(s + ".out");
}
// #define TEST_CASES
void solve() {
int n, t, m;
cin >> n >> t >> m;
vector<vector<pi>> e(n + 5);
for (int i = 0; i < n - 1; i++) {
int u, v; cin >> u >> v;
e[u].pb({v, i}); e[v].pb({u, i});
}
vector<bool> mark(n + 5, false);
vector<int> path;
function<bool(int, int)> dfs_path = [&](int f, int p) -> bool {
if (f == t) { return true; }
for (const auto &[to, id] : e[f]) {
if (to == p) continue;
if (dfs_path(to, f)) {
path.pb(f);
mark[id] = true;
return true;
}
}
};
dfs_path(m, -1);
vector<int> dp(n + 5, 0);
function<void(int, int)> dfs = [&](int f, int p) {
vector<pair<int, bool>> al;
for (const auto &[to, id] : e[f]) {
if (to == p) continue;
dfs(to, f);
al.pb({dp[to], mark[id]});
}
sort(rall(al));
int sz = al.size();
if (sz > 1) {
dp[f] = al[1].ft + !al[1].sd + sz - 1;
} else if (sz == 1) {
dp[f] = !al[0].sd;
}
};
dfs(m, -1);
cout << dp[m];
}
int main() {
setIO();
int tt = 1;
#ifdef TEST_CASES
cin >> tt;
#endif
while (tt--)
solve();
return 0;
}
Compilation message
mousetrap.cpp: In function 'void setIn(std::string)':
mousetrap.cpp:44:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
44 | void setIn(string s) {freopen(s.c_str(), "r", stdin);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp: In function 'void setOut(std::string)':
mousetrap.cpp:45:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
45 | void setOut(string s) {freopen(s.c_str(), "w", stdout);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp: In lambda function:
mousetrap.cpp:73:5: warning: control reaches end of non-void function [-Wreturn-type]
73 | };
| ^
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
313 ms |
80280 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
