Submission #739417

#	Time	Username	Problem	Language	Result	Execution time	Memory
739417		nguyentunglam	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	83 ms	23360 KiB

catinatree

#include<bits/stdc++.h>
#define fi first
#define se second
#define endl "\n"
#define ii pair<int, int>
using namespace std;
const int N = 2e5 + 10;
int f[N], g[N];
vector<int> adj[N];
int n, d;
void dfs(int u) {
    f[u] = d;
    vector<int> lst;
    for(int &v : adj[u]) {
        dfs(v);
        lst.push_back(f[v] + 1);
        g[u] += g[v];
    }
    sort(lst.begin(), lst.end(), greater<int>());
    int cnt = 0;
    for(int &j : lst) if (j + f[u] >= d) {
        f[u] = j;
        cnt++;
    }
    g[u] -= adj[u].size() - cnt;
    if (f[u] == d) g[u]++, f[u] = 0;
}
int main() {
    #define task ""
    cin.tie(0) -> sync_with_stdio(0);
    if (fopen ("task.inp", "r")) {
        freopen ("task.inp", "r", stdin);
        freopen ("task.out", "w", stdout);
    }
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    cin >> n >> d;
    for(int i = 1; i < n; i++) {
        int x; cin >> x;
        adj[x].push_back(i);
    }
    dfs(0);
    cout << g[0];
}

Compilation message (stderr)

catinatree.cpp: In function 'int main()':
catinatree.cpp:32:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         freopen ("task.inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:33:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         freopen ("task.out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:36:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:37:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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