Submission #986521

#	Time	Username	Problem	Language	Result	Execution time	Memory
986521		HiepVu217	Papričice (COCI20_papricice)	C++17	110 / 110	198 ms	27564 KiB

papricice

#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
const int oo = 1e9;
#define sz(a) (int)a.size()
#define eb emplace_back
using pii = pair<int, int>;
int n;
 
namespace arcv {
    int n;
    vector<int> adj[N];
    int par[N];
    int sz[N];
    int st[N];
    int en[N];
    int tour[N];
    int ans = oo;
    int times = 0;
    multiset<int> S;
 
    void calc_sz(int u, int p) {
        par[u] = p;
        sz[u] = 1;
 
        for(int v : adj[u]) {
            if(v == p)
                continue;
 
            calc_sz(v, u);
            sz[u] += sz[v];
        }
    }
 
    int get(int a, int b, int c) {
        return max({a, b, c}) - min({a, b, c});
    }
 
    void DFS1(int u, int p) {
        auto it = S.lower_bound((n - sz[u]) / 2);
 
        if(it != S.end())
            ans = min(ans, get(sz[u], *it, n - sz[u] - (*it)));
 
        if(it != S.begin())
            --it;
 
            ans = min(ans, get(sz[u], *it, n - sz[u] - (*it)));
 
        for(int v : adj[u]) {
            if(v == p)
                continue;
 
            DFS1(v, u);
        }
 
        S.emplace(sz[u]);
        en[u] = times;
    }
 
    void DFS2(int u, int p) {
        auto it = S.lower_bound((n + sz[u]) / 2);
 
        if(it != S.end())
            ans = min(ans, get((*it) - sz[u], sz[u], n - (*it)));
 
        if(it != S.begin())
            --it;
 
        if(it != S.end())
            ans = min(ans, get((*it) - sz[u], sz[u], n - (*it)));
 
        S.emplace(sz[u]);
 
        for(int v : adj[u]) {
            if(v == p)
                continue;
 
            DFS2(v, u);
        }
 
        S.erase(S.find(sz[u]));
    }
 
    void solution() {
        cin >> n;
 
        for(int i = 1; i < n; i++) {
            int u, v;
            cin >> u >> v;
            adj[u].eb(v);
            adj[v].eb(u);
        }
 
        calc_sz(1, 0);
        DFS1(1, 0);
        S.clear();
        DFS2(1, 0);
 
        cout << ans;
    }
}
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    arcv::solution();
}

Compilation message (stderr)

papricice.cpp: In function 'void arcv::DFS1(int, int)':
papricice.cpp:45:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   45 |         if(it != S.begin())
      |         ^~
papricice.cpp:48:13: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   48 |             ans = min(ans, get(sz[u], *it, n - sz[u] - (*it)));
      |             ^~~

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