Submission #727267

#	Time	Username	Problem	Language	Result	Execution time	Memory
727267		Nelt	Race (IOI11_race)	C++17	0 / 100	3 ms	5076 KiB

race

#include "race.h"

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,avx2,fma")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

/* DEFINES */
#define S second
#define F first
#define ll long long
#define ull unsigned long long
#define ld long double
#define npos ULLONG_MAX
#define INF LLONG_MAX
#define vv(a) vector<a>
#define pp(a, b) pair<a, b>
#define pq(a) priority_queue<a>
#define qq(a) queue<a>
#define ss(a) set<a>
#define mm(a, b) map<a, b>
#define ump(a, b) unordered_map<a, b>
#define sync                      \
    ios_base::sync_with_stdio(0); \
    cin.tie(0);                   \
    cout.tie(0);
#define elif else if
#define endl "\n"
#define allc(a) begin(a), end(a)
#define all(a) a, a + sizeof(a) / sizeof(a[0])
#define pb push_back
#define logi(a) __lg(a)
#define sqrt(a) sqrtl(a)
#define mpr make_pair
#define ins insert
using namespace std;
using namespace __gnu_pbds;
using namespace __cxx11;
typedef char chr;
typedef basic_string<chr> str;
template <typename T, typename key = less<T>>
using ordered_set = tree<T, null_type, key, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll N = 2e5 + 5;
vv(pp(ll, ll)) g[N];
ll sub[N], used[N], depth[N], depth1[N];
void dfs(ll v, ll par)
{
    sub[v] = 1;
    for (auto [to, w] : g[v])
        if (!used[to] and to != par)
            dfs(to, v), sub[v] += sub[to];
}
void dfs1(ll v, ll par, multiset<pp(ll, ll)> &s, vv(ll) & child)
{
    for (auto [to, w] : g[v])
        if (to != par and !used[to])
            depth[to] = depth[v] + 1, depth1[to] = depth[v] + w, dfs1(to, v, s, child);
    s.ins(mpr(depth1[v], depth[v]));
    child.pb(v);
}
ll getcentroid(ll v, ll sz, ll par)
{
    for (auto [to, w] : g[v])
        if (!used[to] and to != par and sub[to] > (sz >> 1))
            return getcentroid(to, sz, v);
    return v;
}
ll findcentroid(ll v)
{
    dfs(v, v);
    return getcentroid(v, sub[v], v);
}
ll solve(ll v, ll k)
{
    ll ans = INF;
    v = findcentroid(v);
    used[v] = true;
    depth[v] = depth1[v] = 0;
    multiset<pp(ll, ll)> s;
    vv(ll) child;
    dfs1(v, v, s, child);
    // cout << v << " ";
    // for (ll i : child)
    //     cout << i << " ";
    // cout << endl;
    child.pop_back();
    if (child.empty())
        return INF;
    ll i = 0, last = 0;
    multiset<pp(ll, ll)>::iterator it;
    for (auto [to, w] : g[v])
    {
        if (used[to])
            continue;
        while (child[i] != to)
            s.erase(s.find(mpr(depth1[child[i]], depth[child[i]]))), i++;
        s.erase(s.find(mpr(depth1[to], depth[to])));
        if (!s.empty())
        {
            i = last;
            while (child[i] != to)
            {
                it = s.lower_bound(mpr(k - depth1[child[i]], -100));
                if (it != s.end() and it->F + depth1[child[i]] == k)
                    ans = min(ans, it->S + depth[child[i]]);
                i++;
            }
            it = s.lower_bound(mpr(k - depth1[to], -100));
                if (it != s.end() and it->F + depth1[to] == k)
                    ans = min(ans, it->S + depth[to]);
        }
        i = last;
        while (child[i] != to)
            s.ins(mpr(depth1[child[i]], depth[child[i]])), i++;
        s.ins(mpr(depth1[to], depth[to]));
        i++;
        last = i;
    }
    for (auto [to, w] : g[v])
        if (!used[to])
            ans = min(ans, solve(to, k));
    return ans;
}
int best_path(int n, int k, int e[][2], int w[])
{
    for (ll i = 0; i < n - 1; i++)
        g[e[i][0]].pb(mpr(e[i][1], w[i])), g[e[i][1]].pb(mpr(e[i][0], w[i]));
    ll ans = solve(0, k);
    return ans == INF ? -1 : ans;
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57