#include <bits/stdc++.h> using namespace std; //#define int long long #define FOR(I, L, R) for(int I(L) ; I <= (int)R ; ++I) #define FOD(I, R, L) for(int I(R) ; I >= (int)L ; --I) #define FOA(I, A) for(auto &I : A) #define print(A,L,R) FOR(OK, L, R){if(A[OK]<=-oo / 10||A[OK]>=oo)cout<<"- ";else cout<<A[OK]<<' ';}cout<<'\n'; #define prints(A) FOA(OK, A){cout<<OK<<' ';}cout << '\n'; #define printz(A,L,R) FOR(OK, 0, L){FOR(KO, 0, R){if(A[OK][KO]>-oo&&A[OK][KO]<oo)cout<<A[OK][KO]<<' ';else cout << "- ";} cout << '\n';}cout << '\n'; #define fs first #define sd second #define ii pair<int,int> #define iii pair<int, ii> #define all(A) A.begin(), A.end() #define quickly ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); #define FILE "catinatree" #define pow ladsf const int N = 2e5 + 5; const int SQRT = 505; const int mod = 1e9 + 7; const int oo = 1e18; int n, k, limit, ans; int dp[N][SQRT + 5], sz[N]; vector<int> g[N]; namespace LessSQRT{ static int f[N]; void DFS(int u, int par){ sz[u] = 1; FOA(v, g[u]){ if(v == par){ continue; } DFS(v, u); } dp[u][0] = 1; FOA(v, g[u]){ if(v == par){ continue; } FOR(i, 0, min(limit, sz[u])){ f[i] = dp[u][i]; } FOR(i, 0, min(limit, sz[u])){ FOR(j, 0, min(limit, sz[v])){ if(i + j + 1 >= k){ dp[u][min(i, j + 1)] = max(dp[u][min(i, j + 1)], dp[v][j] + f[i]); } } } FOR(i, 0, min(limit, sz[v])){ dp[u][i + 1] = max(dp[u][i + 1], dp[v][i]); } FOD(i, min(limit, sz[u]), 0){ dp[u][i] = max(dp[u][i], dp[u][i + 1]); } sz[u] += sz[v]; } FOD(i, min(limit, sz[u]), 0) ans = max(ans, dp[u][i]); } void solve(){ DFS(0, -1); } } namespace MoreSQRT{ static int sz[N]; void DFS(int u, int par){ sz[u] = 1; memset(dp[u], -0x3f, sizeof dp[u]); dp[u][0] = oo; dp[u][1] = 0; FOA(v, g[u]){ if(v == par){ continue; } DFS(v, u); FOD(i, min(sz[u], limit), 0){ FOR(j, 0, min(sz[v], limit)){ if(dp[u][i] + dp[v][j] + 1 >= k){ dp[u][i + j] = max(dp[u][i + j], min(dp[u][i], dp[v][j] + 1)); } } } sz[u] += sz[v]; } } void solve(){ DFS(1, -1); FOR(u, 0, n - 1){ FOD(i, limit, 0){ if(dp[u][i] >= 0){ ans = max(ans, i); } } } } } signed main(){ quickly if(fopen(FILE".inp", "r")){ freopen(FILE".inp", "r", stdin); freopen(FILE".out", "w", stdout); } cin >> n >> k; limit = (n - 1) / k + 1; ++limit; FOR(v, 1, n - 1){ int u; cin >> u; g[u].push_back(v); g[v].push_back(u); } if(limit <= k){ MoreSQRT::solve(); } else{ LessSQRT::solve(); } cout << ans; }

catinatree.cpp:28:16: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   28 | const int oo = 1e18;
      |                ^~~~
catinatree.cpp: In function 'int main()':
catinatree.cpp:128:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  128 |                 freopen(FILE".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:129:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |                 freopen(FILE".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~