Submission #1268209

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268209		BlockOG	경주 (Race) (IOI11_race)	C++20	0 / 100	5 ms	9800 KiB

race

#include <bits/stdc++.h>

// mrrrow meeow :3
// go play vivid/stasis now! it's free on steam

#define fo(i, a, b) for (auto i = (a); i < (b); i++)
#define of(i, a, b) for (auto i = (b); i-- > (a);)
#define f first
#define s second
#define pb push_back
#define pob pop_back
#define lb lower_bound
#define ub upper_bound
#define be(a) a.begin(), a.end()
using namespace std;

int ____init = [] {
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    return 0;
}();

map<int, int> adj[200000];
int n, k;
bool did = false;

map<long long, int> dfs2(int i, int p = -1, int d = 0, long long l = 0) {
    if (l >= k) return {};

    map<long long, int> m = {{l, d}};
    for (auto [j, jl] : adj[i]) {
        if (j == p) continue;
        map<long long, int> rm = dfs2(j, i, d + 1, l + jl);
        if (rm.size() > m.size()) swap(rm, m);
        for (auto [cl, cd] : rm) {
            if (m.count(cl)) m[cl] = min(m[cl], cd);
            else m[cl] = cd;
        }
    }

    return m;
}

int dfs1(int i, int s = n, int p = -1) {
    int res = 1;
    int ash = true;

    map<int, int> sizes;
    for (auto [j, l] : adj[i]) {
        if (j == p) continue;
        int jres = dfs1(j, s, i);
        if (did) return jres;
        sizes[j] = jres;
        res += jres;
        ash = ash && jres <= s / 2;
    }

    if (p != -1) ash = ash && s - res <= s / 2, sizes[p] = s - res;
    if (ash) {
        res = 1000000;
        map<long long, int> m;
        for (auto [j, l] : adj[i]) {
            map<long long, int> rm = dfs2(j, i, 1, l);
            if (rm.size() > m.size()) swap(rm, m);
            for (auto [cl, d] : rm) {
                if (m.count(k - cl)) res = min(res, d + m[k - cl]);
            }
            for (auto [cl, d] : rm) {
                if (m.count(cl)) m[cl] = min(m[cl], d);
                else m[cl] = d;
            }

            adj[j].erase(i);
            res = min(res, dfs1(j, sizes[j]));
            did = false;
            adj[j][i] = l;
        }

        did = true;
        return res;
    }

    return res;
}

int best_path(int N, int K, int h[][2], int l[]) {
    n = N, k = K;
    fo(i, 0, n - 1) {
        adj[h[i][0]][h[i][1]] = l[i];
        adj[h[i][1]][h[i][0]] = l[i];
    }

    int res = dfs1(0);
    return res == 1000000 ? -1 : res;
}

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