Submission #647910

#	Time	Username	Problem	Language	Result	Execution time	Memory
647910		ghostwriter	Railway (BOI17_railway)	C++14	100 / 100	114 ms	25260 KiB

railway

#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#else
#define debug(...)
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
template<typename T> T gcd(T a, T b) { return (b == 0? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
#define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
#define FRN(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define FSN(i, n) for (int (i) = (n) - 1; (i) >= 0; --(i))
#define EACH(i, x) for (auto &(i) : (x))
#define WHILE while
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
    Tran The Bao - ghostwriter
    Training for VOI23 gold medal
----------------------------------------------------------------
    DIT ME CHUYEN BAO LOC
----------------------------------------------------------------
*/
const int N = 1e5 + 1;
int n, m, k, tin[N], pe[N], s[N], h[N], p[N][17], timer = 0;
pi e[N];
vi adj[N], ans;
bool cmp(const int &a, const int &b) { return tin[a] < tin[b]; }
int lca(int a, int b) {
	if (h[a] > h[b]) swap(a, b);
	int diff = h[b] - h[a];
	FOR(i, 0, 16)
		if (diff & (1 << i))
			b = p[b][i];
	if (a == b) return a;
	FOS(i, 16, 0)
		if (p[a][i] != p[b][i]) {
			a = p[a][i];
			b = p[b][i];
		}
	return p[a][0];
}
void dfs(int u, int p) {
	tin[u] = ++timer;
	::p[u][0] = p;
	FOR(i, 1, 16) ::p[u][i] = ::p[::p[u][i - 1]][i - 1];
	EACH(j, adj[u]) {
		int v = (e[j].st == u? e[j].nd : e[j].st);
		if (v == p) continue;
		pe[v] = j;
		h[v] = h[u] + 1;
		dfs(v, u);
	}
}
void dfs1(int u, int p) {
	EACH(j, adj[u]) {
		int v = (e[j].st == u? e[j].nd : e[j].st);
		if (v == p) continue;
		dfs1(v, u);
		s[u] += s[v];
	}
	if (s[u] >= k && pe[u]) ans.pb(pe[u]);
}
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);
    cin >> n >> m >> k;
    FOR(i, 1, n - 1) {
    	int a, b;
    	cin >> a >> b;
    	e[i] = {a, b};
    	adj[a].pb(i);
    	adj[b].pb(i);
    }
    dfs(1, 0);
    FOR(i, 1, m) {
    	int s;
    	cin >> s;
    	vi a(s);
    	EACH(j, a) cin >> j;
    	sort(all(a), cmp);
    	int LCA = a[0], prev = a[0];
    	FOR(j, 1, s - 1) {
    		int nLCA = lca(prev, a[j]);
    		++::s[a[j]];
    		--::s[nLCA];
    		if (h[nLCA] < h[LCA]) {
    			++::s[LCA];
    			--::s[nLCA];
    			LCA = nLCA;
    		}
    		prev = a[j];
    	}
    }
    dfs1(1, 0);
    sort(all(ans));
    cout << sz(ans) << '\n';
    EACH(i, ans) cout << i << ' ';
    return 0;
}
/*
6 3 2
1 3
2 3
3 4
6 4
4 5
4 1 3 2 5
2 6 3
2 3 2
----------------------------------------------------------------
From Benq:
    stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/

Compilation message (stderr)

railway.cpp: In function 'int lca(int, int)':
railway.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
railway.cpp:59:2: note: in expansion of macro 'FOR'
   59 |  FOR(i, 0, 16)
      |  ^~~
railway.cpp:33:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   33 | #define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
      |                               ^
railway.cpp:63:2: note: in expansion of macro 'FOS'
   63 |  FOS(i, 16, 0)
      |  ^~~
railway.cpp: In function 'void dfs(int, int)':
railway.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
railway.cpp:73:2: note: in expansion of macro 'FOR'
   73 |  FOR(i, 1, 16) ::p[u][i] = ::p[::p[u][i - 1]][i - 1];
      |  ^~~
railway.cpp:36:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   36 | #define EACH(i, x) for (auto &(i) : (x))
      |                               ^
railway.cpp:74:2: note: in expansion of macro 'EACH'
   74 |  EACH(j, adj[u]) {
      |  ^~~~
railway.cpp: In function 'void dfs1(int, int)':
railway.cpp:36:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   36 | #define EACH(i, x) for (auto &(i) : (x))
      |                               ^
railway.cpp:83:2: note: in expansion of macro 'EACH'
   83 |  EACH(j, adj[u]) {
      |  ^~~~
railway.cpp: In function 'int main()':
railway.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
railway.cpp:96:5: note: in expansion of macro 'FOR'
   96 |     FOR(i, 1, n - 1) {
      |     ^~~
railway.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
railway.cpp:104:5: note: in expansion of macro 'FOR'
  104 |     FOR(i, 1, m) {
      |     ^~~
railway.cpp:36:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   36 | #define EACH(i, x) for (auto &(i) : (x))
      |                               ^
railway.cpp:108:6: note: in expansion of macro 'EACH'
  108 |      EACH(j, a) cin >> j;
      |      ^~~~
railway.cpp:32:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
railway.cpp:111:6: note: in expansion of macro 'FOR'
  111 |      FOR(j, 1, s - 1) {
      |      ^~~
railway.cpp:36:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   36 | #define EACH(i, x) for (auto &(i) : (x))
      |                               ^
railway.cpp:126:5: note: in expansion of macro 'EACH'
  126 |     EACH(i, ans) cout << i << ' ';
      |     ^~~~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25