Submission #129647

#	Time	Username	Problem	Language	Result	Execution time	Memory
129647		Vardanyan	Cat in a tree (BOI17_catinatree)	C++14	0 / 100	6 ms	5112 KiB

catinatree

#include <bits/stdc++.h>
using namespace std;
const int N = 2*1000*100+5;
vector<int> g[N];
int mark[N];
int depth[N];
int par[N];
void dfs(int v,int p = -1){
   if(p!=-1) depth[v] = depth[p]+1;
   par[v] = p;
    for(int i = 0;i<g[v].size();i++){
        int to = g[v][i];
        if(to == p) continue;
        dfs(to,v);
    }

}
bool cmp(int a,int b){
    return depth[a]>depth[b];
}
bool col[N];
int d;
int mr = 0;
int nw;
void go(int v,int dd = 0,int p = -1){
    if(dd>=d) return;
    mark[v] = 1;
    mr++;
    for(int i = 0;i<g[v].size();i++){
        int to = g[v][i];
        if(to == p || to == nw) continue;
        go(to,dd+1,v);
    }
}
int dp[5005][5005];
int ans = 1;
int  n;
void calc(int v,int p = -1){
    if(g[v].size() == 1){
        if(g[v][0] == p){
            dp[v][0] = 1;
            if(v == 0) ans = max(ans,dp[v][0]);
            return;
        }
    }
    for(int i = 0;i<g[v].size();i++){
        int to = g[v][i];
        if(to == p) continue;
        calc(to,v);
    }
    for(int j = 1;j<=n;j++){
        for(int i = 0;i<g[v].size();i++){
            int to = g[v][i];
            if(to == p) continue;
            dp[v][j]+=dp[to][j-1];
            if(v == 0 && j>=d) ans = max(ans,dp[v][j]);
        }
    }
    for(int j = d;j<=d;j++){
        for(int i = 0;i<g[v].size();i++){
            int to = g[v][i];
            if(to == p) continue;
            dp[v][0]+=dp[to][j];
            if(v == 0) ans = max(ans,dp[v][0]);
        }
    }
    dp[v][0] = max(dp[v][0],1);
}
int main(){
    ios_base::sync_with_stdio(false);
    cin>>n>>d;
    for(int i = 1;i<=n-1;i++){
        int x;
        cin>>x;
        g[i].push_back(x);
        g[x].push_back(i);
    }
    dfs(0);
    long long x = (n/d)*n;
    if(x>=0){
        calc(0);
        cout<<ans<<endl;
        return 0;
    }
    vector<int> v;
    for(int i = 0;i<n;i++) v.push_back(i);
    sort(v.begin(),v.end(),cmp);
    int ans = 0;
    int num = 1;
    for(int jj = 0;jj<n;jj++){
        int i = v[jj];
        if(mark[i]) continue;
        mark[i] = 1;
        ans++;
        nw = i;
        go(par[i],1);
    //    if(mr == n) break;

 //       for(int i = 0;i<n;i++) cout<<mark[i]<<" ";
 //       cout<<endl;
    }
    cout<<max(1,ans)<<endl;

    return 0;
}

Compilation message (stderr)

catinatree.cpp: In function 'void dfs(int, int)':
catinatree.cpp:11:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i<g[v].size();i++){
                   ~^~~~~~~~~~~~
catinatree.cpp: In function 'void go(int, int, int)':
catinatree.cpp:29:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i<g[v].size();i++){
                   ~^~~~~~~~~~~~
catinatree.cpp: In function 'void calc(int, int)':
catinatree.cpp:46:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i<g[v].size();i++){
                   ~^~~~~~~~~~~~
catinatree.cpp:52:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0;i<g[v].size();i++){
                       ~^~~~~~~~~~~~
catinatree.cpp:60:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0;i<g[v].size();i++){
                       ~^~~~~~~~~~~~
catinatree.cpp: In function 'int main()':
catinatree.cpp:89:9: warning: unused variable 'num' [-Wunused-variable]
     int num = 1;
         ^~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 40
• Subtask 3: 0 / 49