제출 #1199388

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1199388		Valters07	Race (IOI11_race)	C++20	100 / 100	317 ms	40000 KiB

race

#include <bits/stdc++.h>
#include "race.h"
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
#define fio ios_base::sync_with_stdio(0);cin.tie(0);
#define ll long long
#define ld long double
#define en exit(0);
#define pb push_back
#define fi first
#define se second
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int N = 2e5 + 5;
const int K = 1e6 + 5;
const int INF = 1e9 + 5;
vector<pair<int,int> > g[N];
vector<int> vert, vals;
int best[K], sub[N], len[N];
ll dist[N];
int k, res = INF;
bool ban[N];
int get_centroid(int u, int p, int sz)
{
    sub[u] = 1;
    int mx = -1;
    for(auto [v, w] : g[u])
    {
        if(!ban[v] && v != p)
        {
            int t = get_centroid(v, u, sz);
            if(t != -1)
                return t;
            sub[u] += sub[v];
            mx = max(mx, sub[v]);
        }
    }
    mx = max(mx, sz - sub[u]);
    if(mx <= sz / 2)
        return u;
    return -1;
}
void dfs(int u, int p)
{
    for(auto [v, w] : g[u])
    {
        if(!ban[v] && v != p)
        {
            len[v] = len[u] + 1;
            dist[v] = dist[u] + w;
            dfs(v, u);
        }
    }
    vert.pb(u);
}
void go(int u)
{
    int sz = sub[u];
    u = get_centroid(u, u, sz);
    get_centroid(u, u, sz);
    ban[u] = 1;
    for(auto [v, w] : g[u])
    {
        if(!ban[v])
        {
            vert.clear();
            dist[v] = w;
            len[v] = 1;
            dfs(v, v);
            for(auto x : vert)
            {
                ll l = len[x], d = dist[x];
                if(k - d >= 0)
                    res = min(1ll * res, l + best[k - d]);
            }
            for(auto x : vert)
            {
                ll l = len[x], d = dist[x];
                if(d <= k)
                {
                    best[d] = min(1ll * best[d], l);
                    vals.pb(d);
                }
            }
        }
    }
    for(auto x : vals)
        best[x] = INF;
    best[0] = 0;
    vals.clear();
    for(auto [v, w] : g[u])
        if(!ban[v])
            go(v);
}
int best_path(int N, int K, int H[][2], int L[])
{
    k = K;
    for(int i = 0;i <= k;i++)
        best[i] = INF;
    best[0] = 0;
    for(int i = 0;i < N - 1;i++)
    {
        int u = H[i][0], v = H[i][1], w = L[i];
        g[u].pb({v, w});
        g[v].pb({u, w});
    }
    sub[0] = N;
    go(0);
    return (res == INF ? -1 : res);
}

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