Submission #1121006

#	Time	Username	Problem	Language	Result	Execution time	Memory
1121006		steveonalex	Papričice (COCI20_papricice)	C++17	110 / 110	239 ms	41684 KiB

papricice

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()

ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}

ll gcd(ll a, ll b){return __gcd(a, b);}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ll mask){return __builtin_ctzll(mask);}
int logOf(ll mask){return __lg(mask);}

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}

template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }

template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }

template <class T>
    void printArr(T& container, string separator = " ", string finish = "\n"){
        for(auto item: container) cout << item << separator;
        cout << finish;
    }


template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

const int N = 2e5 + 69;
int n;
vector<int> graph[N];
int sz[N];
set<int> S[N];
int ans = 1e9;

void find_sz(int u, int p){
    sz[u] = 1;
    for(int v: graph[u]) if (v != p){
        find_sz(v, u);
        sz[u] += sz[v];
    }
}

pair<int, int> get_upper_lower(set<int> &S, int x){
    pair<int, int> range = {-1, -1};
    auto it = S.lower_bound(x);
    if (it != S.end()) range.second = *it;
    if (it != S.begin()) {
        it--;
        range.first = *it;
    }
    return range;
}

void dfs(int u, int p){
    for(int v: graph[u]) if (v != p){
        dfs(v, u);
        if (S[u].size() < S[v].size()) swap(S[u], S[v]);
        for(int i: S[v]) {
            pair<int, int> range = get_upper_lower(S[u], (n - i) / 2);
            minimize(ans, max({range.first, n - range.first - i, i}) - min({range.first, n - range.first - i, i}));
            minimize(ans, max({range.second, n - range.second - i, i}) - min({range.second, n - range.second - i, i}));
        }
        for(int i: S[v]){
            S[u].insert(i); 
        }
    }

    if (!S[u].empty()){
        pair<int, int> range = get_upper_lower(S[u], sz[u] / 2);
        minimize(ans, max({range.first, sz[u] - range.first, n - sz[u]}) - min({range.first, sz[u] - range.first, n - sz[u]}));
        minimize(ans, max({range.second, sz[u] - range.second, n - sz[u]}) - min({range.second, sz[u] - range.second, n - sz[u]}));
    }

    S[u].insert(sz[u]);
}

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

    find_sz(1, 0);
    dfs(1, 0);
    cout << ans << "\n";
}

int main(void){
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    clock_t start = clock();
    
    solve();

    cerr << "Time elapsed: " << clock() - start << "ms!\n";
    return 0;
}

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