Submission #589414

#	Time	Username	Problem	Language	Result	Execution time	Memory
589414		Do_you_copy	Cat in a tree (BOI17_catinatree)	C++14	100 / 100	158 ms	18380 KiB

catinatree

#include <bits/stdc++.h>
#define taskname "test"
#define fi first
#define se second
#define pb push_back
#define faster ios_base::sync_with_stdio(0); cin.tie(0);
using namespace std;
using ll = long long;
using pii = pair <int, int>;
using pil = pair <int, ll>;
using pli = pair <ll, int>;
using pll = pair <ll, ll>;
using ull = unsigned ll;
mt19937 Rand(chrono::steady_clock::now().time_since_epoch().count());

ll min(const ll &a, const ll &b){
    return (a < b) ? a : b;
}

ll max(const ll &a, const ll &b){
    return (a > b) ? a : b;
}

//const ll Mod = 1000000009;
//const ll Mod2 = 999999999989;
//only use when required
const int maxN = 2e5 + 1;

int n, d;
int depth[maxN];
int a[maxN];
int deg[maxN];
vector <int> adj[maxN];
bool visited[maxN];

void predfs(int u, int p){
    for (const int &i: adj[u]){
        if (i == p) continue;
        depth[i] = depth[u] + 1;
        predfs(i, u);
    }
}

void dfs(int u, int p, int d){
    visited[u] = 1;
    if (d <= deg[u]) return;
    deg[u] = d;
    for (const int &i: adj[u]){
        if (i == p) continue;
        dfs(i, u, d - 1);
    }
}

void Init(){
    cin >> n >> d;
    for (int i = 1; i < n; ++i){
        int u; cin >> u;
        adj[u].pb(i);
        adj[i].pb(u);
    }
    predfs(0, 0);
    iota(a, a + n, 0);
    sort(a, a + n,[](const auto &i, const auto &j){
        return depth[i] > depth[j];
    });
    int ans = 0;
    for (int i = 0; i < n; ++i){
        if (!deg[a[i]]){
            dfs(a[i], a[i], d);
            ++ans;
        }
    }
    cout << ans;
}

int main(){
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        //freopen(taskname".out", "w", stdout);
    }
    faster;
    ll tt = 1;
    //cin >> tt;
    while (tt--){
        Init();
    }
}

Compilation message (stderr)

catinatree.cpp: In function 'int main()':
catinatree.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 40 / 40
• Subtask 3: 49 / 49