제출 #94466

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
94466		jasony123123	Museum (CEOI17_museum)	C++11	80 / 100	3050 ms	19352 KiB

museum

#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 = 1e15;
/**************************CEOI17 Day 0 P3 - Museum**************************************/
typedef vector<array<ll, 2>> dpvec;

int N, K, X;
dpvec dp[10001];
v<pii> adj[10001];

void update(dpvec &cur, dpvec &add, int cost, int biggest) {
	RFORE(cn, biggest, 1) {
		FOR(an, 1, add.size()) if (an + cn <= K) {
			if (cur[cn][0] != INF) {
				minn(cur[cn + an][0], cur[cn][0] + add[an][0] + cost * 2);
				minn(cur[cn + an][1], cur[cn][0] + add[an][1] + cost);
			}
			if (cur[cn][1] != INF)
				minn(cur[cn + an][1], cur[cn][1] + add[an][0] + cost * 2);
		}
	}
}

int dfs(int x, int p) {
	int subsz = 1;
	v<int> nums;
	for (auto c : adj[x]) if (c.first != p) {
		subsz += dfs(c.first, x);
		nums.push_back(subsz);
	}

	// compute dp[x]
	dp[x].resize(min(K, subsz) + 1, { INF, INF });
	dp[x][1][0] = 0, dp[x][1][1] = 0;
	reverse(all(nums));
	for (auto c : adj[x]) if (c.first != p) {
		update(dp[x], dp[c.first], c.second, nums.back());
		nums.pop_back();
	}

	return subsz;
}

int main() {
	io();
	cin >> N >> K >> X;
	FOR(i, 0, N - 1) {
		int a, b, c; cin >> a >> b >> c;
		adj[a].push_back({ b,c }), adj[b].push_back({ a,c });
	}
	dfs(X, -1);
	cout << dp[X][K][1] << "\n";
	return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 25 / 25
• Subtask 3: 35 / 35
• Subtask 4: 0 / 20