Submission #57738

#	Time	Username	Problem	Language	Result	Execution time	Memory
57738		Benq	Paprike (COI18_paprike)	C++14	100 / 100	170 ms	43648 KiB

paprike

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 100001;

int n,k,h[MX];
vi adj[MX];

pi dfs(int x, int y = 0) {
	pi ret = {h[x],0};
	vi v;
	for (int i: adj[x]) if (i != y) {
		pi a = dfs(i,x);
		ret.s += a.s;
		v.pb(a.f);
	}
	sort(all(v)); reverse(all(v));
	while (sz(v) && ret.f+v.back() <= k) {
		ret.f += v.back(); v.pop_back();
	}
	ret.s += sz(v);
	return ret;
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> n >> k;
	FOR(i,1,n+1) cin >> h[i];
	F0R(i,n-1) {
		int a,b; cin >> a >> b;
		adj[a].pb(b), adj[b].pb(a);
	}
	pi x = dfs(1);
	if (x.f) x.s ++;
	cout << x.s-1;
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 27 / 27
• Subtask 4: 49 / 49