Submission #497764

#	Time	Username	Problem	Language	Result	Execution time	Memory
497764		AlperenT	Papričice (COCI20_papricice)	C++17	110 / 110	245 ms	28332 KiB

papricice

#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 5, INF = 1e9 + 5;

int n, a, b, cnt[N], ans = INF;

multiset<int> anc, oth;

vector<int> tree[N];

void dfs(int v, int p = 0){
    cnt[v] = 1;

    for(auto e : tree[v]){
        if(e != p){
            dfs(e, v);
            cnt[v] += cnt[e];
        }
    }
}

void getans(int x){
    int y, z;

    if(!anc.empty()){
        auto it = anc.lower_bound((n + x) / 2);

        if(it != anc.end()){
            y = *it - x, z = n - *it;

            ans = min(ans, max({x, y, z}) - min({x, y, z}));
        }

        if(it != anc.begin()){
            it = prev(it);

            y = *it - x, z = n - *it;

            ans = min(ans, max({x, y, z}) - min({x, y, z}));
        }
    }

    if(!oth.empty()){
        auto it = oth.lower_bound((n - x) / 2);

        if(it != oth.end()){
            y = *it, z = n - x - y;

            ans = min(ans, max({x, y, z}) - min({x, y, z}));
        }

        if(it != oth.begin()){
            it = prev(it);

            y = *it, z = n - x - y;

            ans = min(ans, max({x, y, z}) - min({x, y, z}));
        }
    }
}

void solve(int v, int p = 0){
    getans(cnt[v]);

    anc.insert(cnt[v]);

    for(auto e : tree[v]){
        if(e != p) solve(e, v);
    }

    anc.erase(anc.find(cnt[v]));
    oth.insert(cnt[v]);
}

int main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);

    cin >> n;

    for(int i = 0; i < n - 1; i++){
        cin >> a >> b;

        tree[a].push_back(b);
        tree[b].push_back(a);
    }

    dfs(1);

    solve(1);

    cout << ans;
}

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