Submission #338697

#	Time	Username	Problem	Language	Result	Execution time	Memory
338697		souvenir_vayne	Papričice (COCI20_papricice)	C++14	0 / 110	3 ms	4972 KiB

papricice

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <chrono>
#define pb push_back
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define int long long
#define endl '\n'
#define ll long long
#define f first
#define fin cin
#define fout cout
#define s second
#define FAST cin.tie(0), cout.tie(0), ios::sync_with_stdio(0)
#define debug(x) cout << "DEBUG " << x << endl
#define debug2(x, y) cout << "DEBUG " << x << " " << y << endl
#define debug3(x, y, z) cout << "DEBUG " << x << " " << y << " " << z<< endl
#define debug4(x, y, z, o) cout << "DEBUG " << x << " " << y << " " << z<< " " << o << endl
#define all(x) x.begin(), x.end()
#define left vadia
#define lb lower_bound
#define right puta
using namespace std;
using namespace __gnu_pbds;
void setIO(string s) {
  ios_base::sync_with_stdio(0); cin.tie(0);
  freopen((s+".in").c_str(),"r",stdin);
  freopen((s+".out").c_str( ),"w",stdout);
}
typedef pair<ll, ll> pii;
typedef vector<vector<char>> mat;
typedef pair<int, string> pis;
const ll mod = 1e9+7;
typedef vector<int> vi;
typedef pair<int, pair<int, int>> piii;

const int MAXN = 2e5 + 5;

int sz[MAXN], n, ans = INT_MAX;
vector<int> g[MAXN];

void get(int u, int p) {
    sz[u] = 1;
    for(int &i : g[u])
        if(i != p) {
            get(i, u);
            sz[u] += sz[i];
        }
}

int calc(int x, int y) {
    int a1 = x, a2 = y - x, a3 = n - y;
    return max({abs(a1 - a2), abs(a1 - a3), abs(a2 - a3)});
}

int calc2(int x, int y) {
    int a1 = x, a2 = y, a3 = n - x - y;
    return max({abs(a1 - a2), abs(a1 - a3), abs(a2 - a3)});
}

set<int> a, b;

void dfs(int u, int p) {

    if(u != 1) {

        int ini = sz[u], mid, end = n, best = (n+sz[u])/2;
        while(ini <= end) {
            mid = (ini + end) >> 1;
            if(calc(sz[u], mid) < calc(sz[u], mid + 1)) {
                end = mid-1;
                if(calc(sz[u], mid) < calc(sz[u], best))
                    best = mid;
            }
            else {
                ini = mid + 2;
                if(calc(sz[u], mid+1) < calc(sz[u], best))
                    best = mid+1;
            }
        }

        auto it = a.upper_bound(best);
        if(it != a.end())
            ans = min(ans, calc(sz[u], *it));
        if(it != a.begin()) {
            it--;
            ans = min(ans, calc(sz[u], *it));
        }

        ini = 0, end = n, best = (n-sz[u])/2;
        while(ini <= end) {
            mid = (ini + end) >> 1;
            if(calc2(sz[u], mid) < calc2(sz[u], mid + 1)) {
                end = mid-1;
                if(calc2(sz[u], mid) < calc2(sz[u], best))
                    best = mid;
            }
            else {
                ini = mid + 2;
                if(calc2(sz[u], mid+1) < calc2(sz[u], best))
                    best = mid+1;
            }
        }

        auto it2 = b.upper_bound(best);
        if(it2 != b.end())
            ans = min(ans, calc2(sz[u], *it));
        if(it2 != b.begin()) {
            it2--;
            ans = min(ans, calc2(sz[u], *it));
        }

    }

    a.insert(sz[u]);
    for(int &i : g[u])
        if(i != p)
            dfs(i, u);
    a.erase(sz[u]);
    b.insert(sz[u]);
}

int32_t main() {

    cin >> n;

    for(int i = 0; i < n-1; i++) {
        int a, b;
        cin >> a >> b;
        g[a].pb(b);
        g[b].pb(a);
    }

    get(1, 1);
    dfs(1, 1);

    cout << ans << endl;


}

Compilation message (stderr)

papricice.cpp: In function 'void setIO(std::string)':
papricice.cpp:27:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   27 |   freopen((s+".in").c_str(),"r",stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
papricice.cpp:28:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   28 |   freopen((s+".out").c_str( ),"w",stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 35
• Subtask 3: 0 / 60