Submission #1129301

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129301		JanPham	Village (BOI20_village)	C++20	0 / 100	2 ms	2628 KiB

Village

#include <bits/stdc++.h>
 
using namespace std;
 
#define pb push_back
#define fi first
#define se second
#define TranLeThanhTam "TranLeThanhTam"
#define all(v) v.begin(),v.end()
#define reset(a,i) memset(a,i,sizeof(a))
#define FOR(i,a,b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i,a,b) for (int i = (a), _b = (b); i >= _b; --i)
#define compact(v) sort(all(v)), v.erase(unique(all(v)), end(v))
#define sz(v) (int) v.size()
#define MASK(i) (1 << (i))
 
typedef long long ll;
typedef long double lb;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
 
const int Thanh_Tam = 1e5 + 17;
const int inf = 1e9 + 17;
const long long infll = 1e18 + 17;
const int MOD = 1e9 + 7;
const int Log = 18;
const int dx[4] = {-1, 0, 0, 1};
const int dy[4] = {0, -1, 1, 0};
const int max_block_size = 270;
const ll P = 311;
const int maxA = 1e2 + 17;
const int addi = 1e9;
const char dir[4] = {'W', 'S', 'N', 'E'};
const int Mod[3] = {998244353, MOD, 759186269};
 
ll mul(ll a, ll b, ll mod);
ll binpow(ll a, ll b, ll mod)
{
    ll res = 1;
    while (b > 0)
    {
        if (b & 1) res = mul(res,a,mod);
        b >>= 1;
        a = mul(a,a,mod);
    }
    return res;
}
ll add(ll a, ll b, ll mod) { return (a + b) % mod;                 }
ll sub(ll a, ll b, ll mod) { return (a - b + mod) % mod;          }
ll mul(ll a, ll b, ll mod) { return ((a % mod) * (b % mod)) % mod; }
ll div(ll a, ll b, ll mod) { return mul(a, binpow(b, mod - 2, mod), mod); }
 
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand_range(ll l, ll r) { return uniform_int_distribution<ll>(l,r)(rng); }

int n, ans_min = 0, ans_max = 0;
vector<int> adj[Thanh_Tam];
int used_min[Thanh_Tam], sz[Thanh_Tam], used_max[Thanh_Tam];

void dp_min(int u, int par)
{
    vector<int> connect_child;
    for (int v : adj[u])
    {
        if (v == par) continue;
        dp_min(v, u);
        if (used_min[v] == 0) connect_child.pb(v);
    }
    
    if (sz(connect_child))
    {
        ans_min += (sz(connect_child) << 1);

        connect_child.pb(u);
        connect_child.pb(connect_child[0]);

        FOR(i,0,sz(connect_child) - 2)
        {
            used_min[connect_child[i]] = connect_child[i + 1];
            sz[connect_child[i]] = sz(connect_child) - 1;
        }
    }    
    else if (par == 0)
    {
        int mx = 0;
        for (int v : adj[u])
            if (sz[v] < sz[mx]) mx = v;
        ans_min += 2;
        used_min[u] = used_min[mx];
        used_min[mx] = u;
    }
    return;
}

pii find_node(int u, int par)
{
    pii node = {0, u};
    for (int v : adj[u])
    {
        if (v == par) continue;
        pii tmp = find_node(v, u);
        if (tmp > node) node = tmp;
    }
    ++node.fi;
    return node;
}

void prepare_dp_max()
{
    int first_node = find_node(1, 0).se, second_node = find_node(first_node, 0).se;
    cout << first_node << ' ' << second_node << '\n';
    return;
}

void ThanhTam()
{
    cin >> n;
    FOR(i,2,n)
    {
        int u,v;
        cin >> u >> v;
        adj[u].pb(v);
        adj[v].pb(u);
        used_min[i] = used_max[i] = 0;
    }

    used_min[1] = used_max[1] = 0;
    sz[0] = 1e9;

    dp_min(1, 0);
    
    cout << ans_min << '\n';
    FOR(i,1,n) cout << used_min[i] << ' ';
    cout << '\n';
    //FOR(i,1,n) cout << used_max[i] << ' ';
    return;
}
 
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
 
    if (fopen(TranLeThanhTam".inp","r"))
    {
        freopen(TranLeThanhTam".inp","r",stdin);
        freopen(TranLeThanhTam".out","w",stdout);
    }
 
    int t = 1;
    //cin >> t;
    while (t--)
        ThanhTam();
 
    return 0;
}

Compilation message (stderr)

Village.cpp: In function 'int main()':
Village.cpp:147:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  147 |         freopen(TranLeThanhTam".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Village.cpp:148:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  148 |         freopen(TranLeThanhTam".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 12
• Subtask 2: 0 / 38
• Subtask 3: 0 / 50