Submission #402502

#	Time	Username	Problem	Language	Result	Execution time	Memory
402502		JerryLiu06	Race (IOI11_race)	C++17	100 / 100	600 ms	93948 KiB

race

#include <bits/stdc++.h>
#include "race.h"
 
using namespace std;
 
using ll = long long;
using db = long double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define mp make_pair
#define f first
#define s second

#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)

const int MOD = 1e9 + 7;
const int MX = 2e5 + 10;
const ll INF = 1e18;

int N, K; ll ans; vpi adj[MX]; unordered_map<ll, ll> M[MX];

void DFS(int X, int P, ll dist, ll depth) {
    M[X][dist] = depth; EACH(Y, adj[X]) if (Y.f != P) {
        DFS(Y.f, X, dist + Y.s, depth + 1); if (sz(M[X]) < sz(M[Y.f])) swap(M[X], M[Y.f]);
        
        EACH(C, M[Y.f]) if (M[X].count(K + 2 * dist - C.f)) ans = min(ans, M[X][K + 2 * dist - C.f] + C.s - 2 * depth);

        EACH(C, M[Y.f]) { if (!M[X].count(C.f)) M[X][C.f] = C.s; else M[X][C.f] = min(M[X][C.f], C.s); }
    }
}
int best_path(int _N, int _K, int H[][2], int L[]) {
    N = _N; K = _K; F0R(i, N - 1) { 
        int A = H[i][0]; int B = H[i][1]; 
        
        adj[A].pb({B, L[i]}), adj[B].pb({A, L[i]});
    }
    ans = INF; DFS(0, -1, 0, 0); return (ans == INF ? -1 : ans);
}

// int main() {
//     ios_base::sync_with_stdio(false); cin.tie(0);

//     cin >> N >> K; F0R(i, N - 1) { int A, B, C; cin >> A >> B >> C; adj[A].pb({B, C}), adj[B].pb({A, C}); }

//     ans = INF; DFS(0, -1, 0, 0); cout << ans;
// }

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