Submission #464393

#	Time	Username	Problem	Language	Result	Execution time	Memory
464393		abc864197532	Papričice (COCI20_papricice)	C++17	110 / 110	510 ms	87664 KiB

papricice

/*
 *   ##   #####   ####      ####  #    #  ####
 *  #  #  #    # #    #    #    # #    # #    #
 * #    # #####  #         #    # #    # #    #
 * ###### #    # #         #    # # ## # #    #
 * #    # #    # #    #    #    # ##  ## #    #
 * #    # #####   ####      ####  #    #  ####
 */
#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair <int, int>
#define X first
#define Y second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define info() cerr << __PRETTY_FUNCTION__ << ": " << __LINE__ << endl
void abc() {cerr << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
    cerr << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
    while (l != r) cout << *l << " \n"[++l == r];
}
template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
    return o >> a.X >> a.Y;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
    return o << '(' << a.X << ", " << a.Y << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
    bool is = false;
    for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
    return o << '}';
}
template <typename T> struct vv : vector <vector <T>> {
    vv(int n, int m, T v) : vector <vector <T>> (n, vector <T>(m, v)) {}
    vv() {}
};
template <typename T> struct vvv : vector <vv <T>> {
    vvv(int n, int m, int k, T v) : vector <vv <T>> (n, vv <T>(m, k, v)) {}
    vvv() {}
};
#ifdef Doludu
#define test(args...) info(), abc("[" + string(#args) + "]", args)
#define owo void(0)
#else
#define test(args...) void(0)
#define owo ios::sync_with_stdio(false); cin.tie(0)
#endif
const int mod = 1e9 + 7, N = 200001, logN = 18, K = 1000;

vector <int> adj[N];
int sz[N];

void dfs_sz(int v, int pa) {
    sz[v] = 1;
    for (int u : adj[v]) if (u != pa) {
        dfs_sz(u, v);
        sz[v] += sz[u];
    }
}

int ans = 1 << 30, n;

void calc(int a, int b, int c) {
    assert(a && b && c);
    ans = min(ans, max({a, b, c}) - min({a, b, c}));
}

multiset <int> pq[N];

void dfs_ans(int v, int pa) {
    for (int u : adj[v]) if (u != pa) {
        dfs_ans(u, v);
        if (pq[v].size() < pq[u].size()) swap(pq[v], pq[u]);
        for (int i : pq[u]) {
            auto it = pq[v].lower_bound((n - i + 1) / 2);
            if (it != pq[v].end()) calc(i, *it, n - i - *it);
            if (it != pq[v].begin()) --it, calc(i, *it, n - i - *it);
        }
        for (int i : pq[u]) pq[v].insert(i);
    }
    if (~pa) {
        auto it = pq[v].lower_bound((sz[v] + 1) / 2);
        if (it != pq[v].end()) calc(n - sz[v], *it, sz[v] - *it);
        if (it != pq[v].begin()) --it, calc(n - sz[v], *it, sz[v] - *it);
        pq[v].insert(sz[v]);
    }
}

int main () {
    owo;
    cin >> n;
    for (int i = 0, u, v; i < n - 1; ++i) {
        cin >> u >> v, --u, --v;
        adj[u].pb(v);
        adj[v].pb(u);
    }
    dfs_sz(0, -1);
    dfs_ans(0, -1);
    cout << ans << endl;
}

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