#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
#include <array>
//#include <ext/pb_ds/tree_policy.hpp>
//#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
//using namespace __gnu_pbds;
#define FOR(i,start,end) for(int i=start;i<(int)(end);i++)
#define FORE(i,start,end) for(int i=start;i<=(int)end;i++)
#define RFOR(i,start,end) for(int i = start; i>end; i--)
#define RFORE(i,start,end) for(int i = start; i>=end; i--)
#define all(a) a.begin(), a.end()
#define mt make_tuple
#define mp make_pair
#define v vector
#define sf scanf
#define pf printf
#define dvar(x) cout << #x << " := " << x << "\n"
#define darr(x,n) FOR(i,0,n) cout << #x << "[" << i << "]" << " := " << x[i] << "\n"
typedef long long ll;
typedef long double ld;
typedef pair<int, int > pii;
typedef pair<ll, ll> pll;
//template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T> void minn(T &a, T b) { a = min(a, b); }
template<class T> void maxx(T &a, T b) { a = max(a, b); }
void io() {
#ifdef LOCAL_PROJECT
freopen("input.in", "r", stdin); freopen("output.out", "w", stdout);
#else
/* online submission */
#endif
ios_base::sync_with_stdio(false); cin.tie(NULL);
}
const ll MOD = 1000000007LL;
const ll PRIME = 105943LL;
const ll INF = 1e12;
/****************************************************************/
const int MAXN = 1e6 + 1;
int N, T, M;
v<int> adj[MAXN];
bool findpath(v<int> &path, int cur, int goal, int par) {
path.push_back(cur);
if (cur == goal) return 1;
for (auto c : adj[cur]) if (c != par) {
if (findpath(path, c, goal, cur)) return 1;
path.pop_back();
}
return 0;
}
pii bad;
ll moves(int x, int p) {
v<ll> cdp = { 0,0 };
int deg = 0;
for (auto c : adj[x]) if (c != p && mp(c, x) != bad && mp(x, c) != bad) {
cdp.push_back(moves(c, x));
deg++;
}
sort(all(cdp), greater<ll>());
return deg + cdp[1];
}
int main() {
io();
cin >> N >> T >> M;
FOR(i, 0, N - 1) {
int a, b; cin >> a >> b;
adj[a].push_back(b), adj[b].push_back(a);
}
v<int> path;
findpath(path, M, T, -1);
// darr(path, path.size());
ll ans = 0;
FOR(i, 0, path.size() - 1) {
bad = { (i-1<0?-1:path[i - 1]), path[i] };
ans += moves(path[i], path[i + 1]);
}
cout << ans << "\n";
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
23 ms |
23800 KB |
Output is correct |
2 |
Correct |
22 ms |
23800 KB |
Output is correct |
3 |
Correct |
23 ms |
23928 KB |
Output is correct |
4 |
Correct |
24 ms |
23800 KB |
Output is correct |
5 |
Incorrect |
23 ms |
23800 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
418 ms |
55160 KB |
Output is correct |
2 |
Correct |
376 ms |
52108 KB |
Output is correct |
3 |
Correct |
1196 ms |
56244 KB |
Output is correct |
4 |
Correct |
516 ms |
40184 KB |
Output is correct |
5 |
Correct |
1165 ms |
56320 KB |
Output is correct |
6 |
Correct |
1162 ms |
56440 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
23 ms |
23800 KB |
Output is correct |
2 |
Correct |
22 ms |
23800 KB |
Output is correct |
3 |
Correct |
23 ms |
23928 KB |
Output is correct |
4 |
Correct |
24 ms |
23800 KB |
Output is correct |
5 |
Incorrect |
23 ms |
23800 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
23 ms |
23800 KB |
Output is correct |
2 |
Correct |
22 ms |
23800 KB |
Output is correct |
3 |
Correct |
23 ms |
23928 KB |
Output is correct |
4 |
Correct |
24 ms |
23800 KB |
Output is correct |
5 |
Incorrect |
23 ms |
23800 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |