Submission #1101268

#	Time	Username	Problem	Language	Result	Execution time	Memory
1101268		huantran	Papričice (COCI20_papricice)	C++17	110 / 110	128 ms	24908 KiB

papricice

#include <iostream>
#include <algorithm>
#include <cstring>
#include <string.h>
#include <vector>
#include <math.h>
#include <map>
#include <set>
#include <queue>
#include <iomanip>
#include <numeric>
#include <random>
#include <chrono>
#include <fstream>
#include <stack>
#include <cmath>
#define bit(x, i) (((x) >> (i)) & 1LL)
#define rand rd
#define PI acos(-1)

using namespace std;
typedef long long int ll;
const int maxn = 2e5 + 5;
const ll mod = 1e9 + 7;
const int inf = 1e9;
const ll base = 1e5 + 7;
using pll = pair<ll, ll>;

const string NAME = "LOCO";
const int NTEST = 100;

mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());

ll Rand(ll l, ll r) {
    return l + rd() % (r - l + 1);
}

int n, cnt = 0;
vector<int> adj[maxn];
int sz[maxn], tin[maxn], tout[maxn];
set<int> is_anc, is_not_anc;

void dfs_sz(int u, int p) {
    tin[u] = ++cnt;
    sz[u] = 1;

    for (auto j : adj[u]) {
        if (j == p)
            continue;
        dfs_sz(j, u);
        sz[u] += sz[j];
    }

    tout[u] = cnt;
}

vector<int> find_pos(set<int> &s, int val) {
    vector<int> res;
    auto it = s.upper_bound(val);
    if (it != s.end())
        res.push_back(*it);
    if (it != s.begin()) {
        --it;
        res.push_back(*it);
    }

    return res;
}

int calc(int a, int b, int c) {
    return max({a, b, c}) - min({a, b, c});
}

int go(int u, int p) {
    is_anc.insert(sz[u]);

    int res = inf;

    for (auto j : find_pos(is_anc, (n + sz[u]) / 2)) {
        res = min(res, calc(sz[u], j - sz[u], n - j));
    }

    for (auto j : find_pos(is_not_anc, (n - sz[u]) / 2)) {
        res = min(res, calc(sz[u], j, n - j - sz[u]));
    }

    for (auto j : adj[u]) {
        if (j == p)
            continue;
        res = min(go(j, u), res);
    }

    is_anc.erase(sz[u]);
    is_not_anc.insert(sz[u]);

    return res;
}

int main() {    
    // #ifndef ONLINE_JUDGE
    //     freopen("TASK.inp", "r", stdin);
    //     freopen("TASK.out", "w", stdout);
    // #endif // ONLINE_JUDGE

    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    cin >> n;
    for (int i = 1; i <= n - 1; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    dfs_sz(1, 1);
    cout << go(1, 1);
}

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 60 / 60