Submission #932986

#	Time	Username	Problem	Language	Result	Execution time	Memory
932986		LucaIlie	Cat in a tree (BOI17_catinatree)	C++17	100 / 100	77 ms	26448 KiB

catinatree

#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 2e5;
int n, d;
int cats[MAX_N], dist[MAX_N];
vector<int> adj[MAX_N];

struct cd {
    int cats, dist;
};

void dfs( int u ) {
    vector<cd> o;

    cats[u] = 0;
    dist[u] = n;
    o.push_back( { 1, 0 } );
    for ( int v: adj[u] ) {
        dfs( v );
        o.push_back( { cats[v], dist[v] + 1 } );
    }

    sort( o.begin(), o.end(), []( cd a, cd b ) {
        return a.dist < b.dist;
    } );

    int i;
    for ( i = 0; i < o.size() - 1; i++ ) {
        if ( o[i].dist + o[i + 1].dist < d )
            cats[u] += o[i].cats - 1;
        else
            break;
    }
    for ( ; i < o.size(); i++ ) {
        cats[u] += o[i].cats;
        dist[u] = min( dist[u], o[i].dist );
    }
}

int main() {
    cin >> n >> d;
    for ( int v = 1; v < n; v++ ) {
        int p;
        cin >> p;
        adj[p].push_back( v );
    }

    dfs( 0 );

    cout << cats[0];

    return 0;
}

Compilation message (stderr)

catinatree.cpp: In function 'void dfs(int)':
catinatree.cpp:30:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<cd>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for ( i = 0; i < o.size() - 1; i++ ) {
      |                  ~~^~~~~~~~~~~~~~
catinatree.cpp:36:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<cd>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |     for ( ; i < o.size(); i++ ) {
      |             ~~^~~~~~~~~~

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