Submission #644789

#	Time	Username	Problem	Language	Result	Execution time	Memory
644789		Vu_CG_Coder	Cat in a tree (BOI17_catinatree)	C++14	100 / 100	528 ms	376528 KiB

catinatree

/* [Author : Hoang Duy Vu] */
#include <bits/stdc++.h>
#define All(x) (x).begin(),(x).end()
#define ll long long
#define C make_pair
#define fi first
#define se second
#define two second.first
#define thr second.second
#define TASK "txt"
using namespace std;
template<typename T> bool maximize(T &res, const T &val) {
    if (res < val) { res = val; return true; } return false; }
template<typename T> bool minimize(T &res, const T &val) {
    if (res > val) { res = val; return true; } return false; }
 
typedef pair<int,int> ii;
typedef pair<int,ii> iii;
const int LOG = 20;
const int INF = 1e9 + 7;
const ll LNF = 1e18 + 7;
const int mod = 1e9 + 7;
const int N = 200010;
 
vector <int> a[N];
int dp[N][450] = {0};
int t[N] = {0};
int f[1100] = {0};
int high[N] = {0};
int n , k;
int sz[N] = {0};
int ans = 0;
 
void input()
{
    cin >> n >> k;
    for (int i = 1 ; i < n ; i++)
    {
        int x;
        cin >> x;
        a[x].push_back(i);
        a[i].push_back(x);
    }
}
 
void dfs(int u ,int par)
{
    memset(dp[u],0,sizeof(dp[u]));
 
    for (int v : a[u])
    if (v != par)
    {
        dfs(v,u);
        maximize(high[u],high[v] + 1);

        for (int i = 0 ; i <= k ; i++) f[i] = dp[u][i];
 
        for (int i = 0 ; i <= min(high[u],k) ; i++)
        {
            for (int j = max(i - 1,0) ; j <= min(high[v],k) ; j++)
            {
                int x = j + 1;
                maximize(dp[u][i],f[max(i,k - x)] + dp[v][j]);
            }
        }
    }
 
    maximize(dp[u][0],dp[u][k] + 1);
}
 
void case1()
{
    dfs(0,0);
 
    int res = 0;
    for (int i = 0 ; i <= high[0] ; i++) maximize(res,dp[0][i]);
 
    cout << res;
}

void DFS(int u , int par)
{
    memset(dp[u],-1,sizeof(dp[u]));
    dp[u][0] = INF;
    sz[u] = 1;
    
    for (int v : a[u])
    if (v != par)
    {
        DFS(v,u);
        sz[u] = min(ans,sz[u] + sz[v]);
    //    cout << u << " " << v << " " << ans << " " << sz[u] << " " << sz[v] << "\n";

        for (int i = 0 ; i <= ans ; i++) f[i] = dp[u][i];

        for (int i = 1 ; i <= sz[u] ; i++) 
        {
            for (int z = 0 ; z <= i ; z++)
            if (f[z] != -1 && dp[v][i - z] != -1 && f[z] + dp[v][i - z] + 1 >= k)
            maximize(dp[u][i],min(f[z],dp[v][i - z] + 1));
        }
    }

    for (int i = 0 ; i <= sz[u] ; i++) if (dp[u][i] >= k) maximize(dp[u][i + 1],0);

   // cout << u << " " << sz[u] << " :";
   // for (int i = 0 ; i <= sz[u] ; i++) cout << dp[u][i] << " ";
   // cout << "\n";
}

void case2()
{
    DFS(0,0);

    int res = 0;

    for (int i = 0 ; i <= sz[0] ; i++) 
    if (dp[0][i] != -1) res = i;

    cout << res;
}

void solve()
{

    ans = (n / k) + 1;

    if (k < ans) case1();
    else case2();
}
 
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(NULL); cout.tie(NULL);
    if(fopen(TASK".inp", "r")){
    freopen(TASK".inp","r",stdin);
    freopen(TASK".out","w",stdout);
    }
 
    int tk;
    tk = 1;
   //cin >> tk;
    while (tk--)
    {
        input();
        solve();
    }
    return 0;
}

Compilation message (stderr)

catinatree.cpp: In function 'int main()':
catinatree.cpp:137:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  137 |     freopen(TASK".inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:138:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  138 |     freopen(TASK".out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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