제출 #742239

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
742239		beaboss	경주 (Race) (IOI11_race)	C++14	100 / 100	493 ms	107516 KiB

race

// #include <bits/stdc++.h>

// using namespace std;

// #define s second
// #define f first
// #define pb push_back

// typedef long long ll;

// typedef pair<ll, ll> pii;
// typedef vector<pii> vpii;

// typedef vector<ll> vi;

// #define FOR(i, a, b) for (ll i = (a); i<b; i++)

// const ll MN = 3e5 + 10;

// vpii adj[MN];
// ll d[MN]; // from root in highways
// ll d2[MN]; // from root in distance
// ll k;
// map<ll, ll> small[MN];
// void dfs(ll cur = 0, ll dist = 0, ll dist2 = 0, ll p = -1) {
//   // cout << cur << endl;
//   d[cur]=dist;
//   d2[cur]=dist2;

//   small[cur][dist2]=dist;

//   for (auto val: adj[cur]) {
//     if (val.f != p) {
//       dfs(val.f, dist + 1ll, dist2 + val.s, cur);
//     }
//   }
// }



// ll ans = 1e9;

// void solve(ll cur, ll p=-1) {
//   ll target = k + 2*d2[cur];
//   for (auto val: adj[cur]) {
//     if (val.f != p) {
//       solve(val.f, cur);

//       if (small[val.f].size() > small[cur].size()) swap(small[val.f], small[cur]);

//       for (pii nx: small[val.f]) {
//         if (small[cur].find(target - nx.f) != small[cur].end()) {
//           ans = min(ans, small[cur][target - nx.f] + nx.s - 2*d[cur]);
//         }
//       }

//       for (pii nx: small[val.f]) {
//         if (small[cur].find(nx.f) == small[cur].end()) small[cur].insert(nx);
//         else small[cur][nx.f]=min(small[cur][nx.f], nx.s);
//       }
//     }

//   }


  
// }



// int best_path(int N, int K, int H[][2], int L[])
// {

//   k = K;
//   FOR(i, 0, N-1) {
//     adj[H[i][0]].pb({H[i][1], L[i]});
//   }

//   dfs();
//   solve(0);
//   if (ans == 1e9) ans = -1;
//   return ans;
// }

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pii;

#define pb push_back

#define f first
#define s second

const int maxn = 2e5 + 1;
vector<pii> adj[maxn];
map<ll, ll> info[maxn];
ll dist[maxn], sum[maxn];  // define these relative to root
int N, K;
ll ret;

void precomp(int u, int p, ll c, int h) {
	info[u][c] = h;
	sum[u] = c;
	dist[u] = h;
	for (auto n : adj[u]) {
		if (p == n.f) { continue; }
		precomp(n.f, u, c + n.s, h + 1);
	}
}

void small_to_large_merge(int u, int p) {
	ll target = K + 2 * sum[u];
	for (auto n : adj[u]) {
		if (n.f == p) { continue; }
		small_to_large_merge(n.f, u);
		if (info[n.f].size() > info[u].size()) { swap(info[n.f], info[u]); }
		for (auto i : info[n.f]) {
			if (info[u].find(target - i.f) != info[u].end()) {
				ret = min(ret, info[u][target - i.f] + i.s - 2 * dist[u]);
			}
		}
		for (auto i : info[n.f]) {
			if (info[u].find(i.f) == info[u].end()) {
				info[u].insert(i);
			} else {
				info[u][i.f] = min(info[u][i.f], i.s);
			}
		}
	}
}

int best_path(int n, int k, int edges[][2], int weights[]) {
	if (k == 1) { return 0; }
	N = n;
	K = k;
	ret = INT_MAX;
	for (int i = 0; i < n - 1; i++) {
		int u = edges[i][0];
		int v = edges[i][1];
		adj[u].pb(pii(v, weights[i]));
		adj[v].pb(pii(u, weights[i]));
	}
	precomp(0, -1, 0, 0);
	small_to_large_merge(0, -1);
	return ret == INT_MAX ? -1 : ret;
}

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57