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Submission #225229

# Submission time Handle Problem Language Result Execution time Memory
225229 2020-04-19T17:25:46 Z MKopchev Cat in a tree (BOI17_catinatree) C++14
100 / 100
 472 ms 156908 KB 
#include<bits/stdc++.h>
using namespace std;
const int nmax=1e6+42;
long long n,d;
vector< pair<int/*to*/,int/*dist*/> > adj[nmax];

long long depth[nmax];

vector<int> output;

int up[20][nmax];

int level[nmax];

int in[nmax],out[nmax];

int seen[nmax],t=0;

pair<int/*min level*/,int/*node*/> table[20][nmax];

void dfs(int node,int par)
{
    up[0][node]=par;

    level[node]=level[par]+1;

    t++;
    in[node]=t;

    seen[t]=node;

    for(auto k:adj[node])
        if(k.first!=par)
        {
            depth[k.first]=depth[node]+k.second;
            dfs(k.first,node);

            t++;
            seen[t]=node;
        }

    t++;
    seen[t]=node;

    out[node]=t;
}

int inv[nmax];

int query(int l,int r)
{
    int k=inv[r-l+1];

    return min(table[k][l],table[k][r-(1<<k)+1]).second;
}
int lca(int u,int v)
{
    return query(min(in[u],in[v]),max(out[u],out[v]));
}
long long tree_dist(int u,int v)
{
    return depth[u]+depth[v]-2*depth[lca(u,v)];
}

bool been[nmax];

int parent_centroid[nmax];

long long nearest[nmax];

int SZ[nmax];

void dfs_sz(int node,int par)
{
    SZ[node]=1;
    for(auto k:adj[node])
        if(k.first!=par&&been[k.first]==0)
        {
            dfs_sz(k.first,node);
            SZ[node]+=SZ[k.first];
        }
}
int centroid(int node)
{
    dfs_sz(node,0);

    int low=SZ[node]/2;

    while(1)
    {
        bool stop=1;
        for(auto k:adj[node])
            if(SZ[node]>SZ[k.first]&&SZ[k.first]>low)
            {
                node=k.first;
                stop=0;
                break;
            }
        if(stop)break;
    }

    return node;
}
int decomp(int node)
{
    node=centroid(node);

    been[node]=1;

    for(auto k:adj[node])
        if(been[k.first]==0)
        {
            parent_centroid[decomp(k.first)]=node;
        }

    return node;
}

priority_queue< pair<long long,int> > pq;

long long closest(int node)
{
    long long ret=1e18;
    int help=node;
    while(help)
    {
        ret=min(ret,tree_dist(node,help)+nearest[help]);
        help=parent_centroid[help];
    }
    return ret;
}

int go_up(int node)
{
    int help=node;
    for(int i=19;i>=0;i--)
        if(depth[node]-depth[up[i][help]]<=d)help=up[i][help];
    return help;
}

void update(int node)
{
    int help=node;
    while(help)
    {
        nearest[help]=min(nearest[help],tree_dist(help,node));
        help=parent_centroid[help];
    }
}
int main()
{
    scanf("%lld%lld",&n,&d);

    int u,v,dist;
    for(int i=1;i<n;i++)
    {
        scanf("%i",&v);
        u=i+1;
        v++;

        //cout<<u<<" "<<v<<endl;

        adj[u].push_back({v,1});
        adj[v].push_back({u,1});
    }

    dfs(1,1);

    for(int i=1;i<=t;i++)
        table[0][i]={level[seen[i]],seen[i]};

    for(int st=1;st<20;st++)
        for(int i=1;i+(1<<st)-1<=t;i++)
            table[st][i]=min(table[st-1][i],table[st-1][i+(1<<(st-1))]);

    for(int i=1;i<=t;i++)
    {
        while(2*(1<<inv[i])<i)inv[i]++;
    }

    for(int st=1;st<20;st++)
        for(int i=1;i<=n;i++)
            up[st][i]=up[st-1][up[st-1][i]];

    decomp(1);
    /*
    for(int i=1;i<=t;i++)
    {
        cout<<seen[i]<<" ";
    }
    cout<<endl;

    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++)
        {
            cout<<lca(i,j)<<" ";
        }
        cout<<endl;
    }


    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++)
        {
            cout<<tree_dist(i,j)<<" ";
        }
        cout<<endl;
    }

    cout<<"t= "<<t<<endl;

    for(int i=1;i<=n;i++)cout<<i<<" -> "<<parent_centroid[i]<<endl;
    */

    for(int i=1;i<=n;i++)nearest[i]=1e18;

    for(int i=1;i<=n;i++)pq.push({depth[i],i});

    while(pq.size())
    {
        pair<long long,int> tp=pq.top();
        pq.pop();
        /*
        cout<<"---"<<endl;

        for(int i=1;i<=n;i++)
            cout<<i<<" -> "<<closest(i)<<endl;
        */

        if(closest(tp.second)<d)continue;

        int actual=tp.second;

        output.push_back(actual);

        update(actual);
        /*
        cout<<"update "<<actual<<endl;

        cout<<"nearest: "<<endl;
        for(int i=1;i<=n;i++)
            cout<<i<<" -> "<<nearest[i]<<endl;
        cout<<"---"<<endl;
        */
    }

    sort(output.begin(),output.end());

    printf("%i\n",output.size());
    /*
    for(int i=0;i<output.size();i++)
    {
        printf("%i",output[i]);
        if(i==output.size()-1)printf("\n");
        else printf(" ");
    }
    */
    return 0;
}

Compilation message

catinatree.cpp: In function 'int main()':
catinatree.cpp:251:32: warning: format '%i' expects argument of type 'int', but argument 2 has type 'std::vector<int>::size_type {aka long unsigned int}' [-Wformat=]
     printf("%i\n",output.size());
                   ~~~~~~~~~~~~~^
catinatree.cpp:154:13: warning: unused variable 'dist' [-Wunused-variable]
     int u,v,dist;
             ^~~~
catinatree.cpp:152:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld%lld",&n,&d);
     ~~~~~^~~~~~~~~~~~~~~~~~
catinatree.cpp:157:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%i",&v);
         ~~~~~^~~~~~~~~

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 24064 KB Output is correct
2 Correct 18 ms 24064 KB Output is correct
3 Correct 18 ms 24064 KB Output is correct
4 Correct 19 ms 24064 KB Output is correct
5 Correct 18 ms 24064 KB Output is correct
6 Correct 18 ms 24064 KB Output is correct
7 Correct 18 ms 24064 KB Output is correct
8 Correct 17 ms 24064 KB Output is correct
9 Correct 17 ms 24064 KB Output is correct
10 Correct 18 ms 24116 KB Output is correct
11 Correct 18 ms 24064 KB Output is correct
12 Correct 19 ms 24040 KB Output is correct
13 Correct 19 ms 24064 KB Output is correct
14 Correct 18 ms 24064 KB Output is correct
15 Correct 18 ms 24064 KB Output is correct
16 Correct 19 ms 24064 KB Output is correct
17 Correct 18 ms 24064 KB Output is correct
18 Correct 18 ms 24064 KB Output is correct
19 Correct 19 ms 24064 KB Output is correct
20 Correct 18 ms 24064 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 24064 KB Output is correct
2 Correct 18 ms 24064 KB Output is correct
3 Correct 18 ms 24064 KB Output is correct
4 Correct 19 ms 24064 KB Output is correct
5 Correct 18 ms 24064 KB Output is correct
6 Correct 18 ms 24064 KB Output is correct
7 Correct 18 ms 24064 KB Output is correct
8 Correct 17 ms 24064 KB Output is correct
9 Correct 17 ms 24064 KB Output is correct
10 Correct 18 ms 24116 KB Output is correct
11 Correct 18 ms 24064 KB Output is correct
12 Correct 19 ms 24040 KB Output is correct
13 Correct 19 ms 24064 KB Output is correct
14 Correct 18 ms 24064 KB Output is correct
15 Correct 18 ms 24064 KB Output is correct
16 Correct 19 ms 24064 KB Output is correct
17 Correct 18 ms 24064 KB Output is correct
18 Correct 18 ms 24064 KB Output is correct
19 Correct 19 ms 24064 KB Output is correct
20 Correct 18 ms 24064 KB Output is correct
21 Correct 19 ms 24960 KB Output is correct
22 Correct 19 ms 24320 KB Output is correct
23 Correct 19 ms 24320 KB Output is correct
24 Correct 18 ms 24320 KB Output is correct
25 Correct 20 ms 24576 KB Output is correct
26 Correct 20 ms 24576 KB Output is correct
27 Correct 19 ms 24576 KB Output is correct
28 Correct 20 ms 24832 KB Output is correct
29 Correct 21 ms 24832 KB Output is correct
30 Correct 20 ms 24832 KB Output is correct
31 Correct 22 ms 25088 KB Output is correct
32 Correct 20 ms 24832 KB Output is correct
33 Correct 20 ms 24832 KB Output is correct
34 Correct 19 ms 24832 KB Output is correct
35 Correct 20 ms 24832 KB Output is correct
36 Correct 20 ms 24960 KB Output is correct
37 Correct 20 ms 24832 KB Output is correct
38 Correct 20 ms 24832 KB Output is correct
39 Correct 20 ms 24832 KB Output is correct
40 Correct 20 ms 24960 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 24064 KB Output is correct
2 Correct 18 ms 24064 KB Output is correct
3 Correct 18 ms 24064 KB Output is correct
4 Correct 19 ms 24064 KB Output is correct
5 Correct 18 ms 24064 KB Output is correct
6 Correct 18 ms 24064 KB Output is correct
7 Correct 18 ms 24064 KB Output is correct
8 Correct 17 ms 24064 KB Output is correct
9 Correct 17 ms 24064 KB Output is correct
10 Correct 18 ms 24116 KB Output is correct
11 Correct 18 ms 24064 KB Output is correct
12 Correct 19 ms 24040 KB Output is correct
13 Correct 19 ms 24064 KB Output is correct
14 Correct 18 ms 24064 KB Output is correct
15 Correct 18 ms 24064 KB Output is correct
16 Correct 19 ms 24064 KB Output is correct
17 Correct 18 ms 24064 KB Output is correct
18 Correct 18 ms 24064 KB Output is correct
19 Correct 19 ms 24064 KB Output is correct
20 Correct 18 ms 24064 KB Output is correct
21 Correct 19 ms 24960 KB Output is correct
22 Correct 19 ms 24320 KB Output is correct
23 Correct 19 ms 24320 KB Output is correct
24 Correct 18 ms 24320 KB Output is correct
25 Correct 20 ms 24576 KB Output is correct
26 Correct 20 ms 24576 KB Output is correct
27 Correct 19 ms 24576 KB Output is correct
28 Correct 20 ms 24832 KB Output is correct
29 Correct 21 ms 24832 KB Output is correct
30 Correct 20 ms 24832 KB Output is correct
31 Correct 22 ms 25088 KB Output is correct
32 Correct 20 ms 24832 KB Output is correct
33 Correct 20 ms 24832 KB Output is correct
34 Correct 19 ms 24832 KB Output is correct
35 Correct 20 ms 24832 KB Output is correct
36 Correct 20 ms 24960 KB Output is correct
37 Correct 20 ms 24832 KB Output is correct
38 Correct 20 ms 24832 KB Output is correct
39 Correct 20 ms 24832 KB Output is correct
40 Correct 20 ms 24960 KB Output is correct
41 Correct 217 ms 143336 KB Output is correct
42 Correct 216 ms 85324 KB Output is correct
43 Correct 200 ms 85100 KB Output is correct
44 Correct 193 ms 84972 KB Output is correct
45 Correct 207 ms 85060 KB Output is correct
46 Correct 472 ms 150512 KB Output is correct
47 Correct 464 ms 150508 KB Output is correct
48 Correct 454 ms 150508 KB Output is correct
49 Correct 457 ms 150508 KB Output is correct
50 Correct 136 ms 85236 KB Output is correct
51 Correct 135 ms 85232 KB Output is correct
52 Correct 134 ms 85232 KB Output is correct
53 Correct 301 ms 151012 KB Output is correct
54 Correct 278 ms 150884 KB Output is correct
55 Correct 292 ms 150888 KB Output is correct
56 Correct 21 ms 25344 KB Output is correct
57 Correct 41 ms 37236 KB Output is correct
58 Correct 141 ms 90224 KB Output is correct
59 Correct 376 ms 156908 KB Output is correct
60 Correct 226 ms 146532 KB Output is correct
61 Correct 304 ms 143768 KB Output is correct