| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1263844 | Yelarys | Race (IOI11_race) | C++20 | 0 ms | 0 KiB |
#include "race.h"
#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define sz(x)(int) x.size()
#define ins insert
#define speed ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr)
#define rep(i, a, b) for (int i = a; i < b; i++)
#define pf push_front
#define pb push_back
#define all(x) x.begin(), x.end()
#define pii pair < int, int >
#define pll pair < ll, ll >
#define vi vector < int >
#define vll vector < long long >
#define vpii vector < pair < int, int >>
#define vpll vector < pair < long long, long long >>
#define mem(x, val) memset(x, val, sizeof x)
#define debug cerr << "OK\n";
mt19937 bruh(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rofl(chrono::steady_clock::now().time_since_epoch().count());
const int inf = 1e9 + 100;
const ll INF = (ll)1e18;
const ll INF1 = (ll)1e14 + 1;
const int MAXN = (int)5e5 + 5;
const ll mod = (ll)1e9 + 7;
const ll mod1 = (ll)1e9 + 9;
const ll MAX = (ll)1e6 + 5;
//const int P = 331;
//const int K = 17;
ll binpow(ll a, ll n) {
if (n == 0) return 1;
if (n == 1) return (a % mod);
ll r = binpow(a, n / 2);
if (n & 1) return (((r * r) % mod) * a) % mod;
return (r * r) % mod;
}
void setIO(string s) {
freopen((s + ".in").c_str(), "r", stdin);
freopen((s + ".out").c_str(), "w", stdout);
}
ll add(ll a, ll b) {
return (((a + b) % mod) + mod) % mod;
}
ll mul(ll a, ll b) {
return (a * b) % mod;
}
int n, k;
map<int, int> ma[MAXN];
int sum[MAXN], d[MAXN];
vector<pii> G[MAXN];
vector<int> g[MAXN];
int ans = inf;
void prec(int v, int par = -1) {
for (auto [u, w] : G[v]) {
if (u == par) continue;
g[v].pb(u);
sum[u] = sum[v] + w;
d[u] = d[v] + 1;
prec(u, v);
}
}
void dfs(int v) {
for (int u : g[v]) {
dfs(u);
}
ma[v][sum[v]] = d[v];
for (int i = 1; i < sz(g[v]); i++) {
int x = g[v][i - 1], y = g[v][i];
if (sz(ma[x]) > sz(ma[y])) swap(ma[x], ma[y]);
for (auto [sx, dx] : ma[x]) {
int sy = k + 2 * sum[v] - sx;
if (ma[y].count(sy)) {
int dy = ma[y][sy];
ans = min(ans, dx + dy - 2 * d[v]);
}
}
for (auto [sx, dx] : ma[x]) {
if (!ma[y].count(sx)) {
ma[y][sx] = dx;
continue;
}
ma[y][sx] = min(ma[y][sx], dx);
}
}
if (sz(g[v])) {
int y = g[v].back();
int sy = k + sum[v];
if (ma[y].count(sy)) {
int dy = ma[y][sy];
ans = min(ans, dy - d[v]);
}
swap(ma[v], ma[y]);
if (!ma[v].count(sum[v])) {
ma[v][sum[v]] = d[v];
} else {
ma[v][sum[v]] = min(ma[v][sum[v]], d[v]);
}
}
}
int best_path(int N, int K, int H[][2], int L[]) {
n = N, k = K;
for (int i = 0; i < N - 1; i++) {
G[H[i][0]].pb({H[i][1], L[i]});
G[H[i][1]].pb({H[i][0], L[i]});
}
prec(0);
dfs(0);
return ans;
}
//int main() {
//
//int H[3][2] = {{0, 1}, {1, 2}, {1, 3}};
//int L[3] = {1, 2, 4};
//cout << best_path(4, 3, H, L);
//}