Submission #1296348

#TimeUsernameProblemLanguageResultExecution timeMemory
1296348hiepsimauhongCat in a tree (BOI17_catinatree)C++20
0 / 100
1 ms332 KiB
#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, 1, 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 "FILE"

const int N = 2e5 + 5;
const int SQRT = 320;

const int mod = 1e9 + 9999;
const int oo = 1e18;

struct Modint{
        int x;

        Modint(){x = 0;}
        Modint(int _x){x = (_x + mod) % mod;}

        Modint operator + (const Modint &other) const{ return Modint((x + other.x) % mod); }
        Modint operator - (const Modint &other) const{ return Modint((x - other.x + mod) % mod); }
        Modint operator * (const Modint &other) const{ return Modint((1LL * x * other.x) % mod); }

        void operator += (const Modint &other) { *this = *this + other; }
        void operator -= (const Modint &other) { *this = *this - other; }
        void operator *= (const Modint &other) { *this = *this * other; }

        friend ostream& operator << (ostream& os, const Modint &other){
                return os << other.x;
        }
};

int n, k;
vector<int> g[N];

namespace SubtaskSQRT{
        static const int M = 1005 + 5;
        static int dp[M][M], pre[M][M], h[M];
        static int opt[M];

        void DFS(int u, int par){
                FOA(v, g[u]){
                        DFS(v, u);
                        h[u] = max(h[u], h[v] + 1);
                }

                FOR(i, 0, h[u]){
                        opt[i] = 0;
                        FOA(v, g[u]){
                                opt[i] += pre[v][max({0LL, i - 1, k - i - 1})];
                        }
                }
                dp[u][0] = opt[k] + 1;

                FOD(i, h[u], 1){
                        FOA(v, g[u]){
                                dp[u][i] = max(dp[u][i], dp[v][i - 1] + opt[i] - pre[v][max({0LL, i - 1, k - i - 1})]);
                        }
                }

                pre[u][0] = dp[u][0];
                FOR(i, 1, h[u]){
                        pre[u][i] = max(dp[u][i], pre[u][i - 1]);
                }
        }

        void solve(){
                DFS(1, -1);

                int ans = 0;
                FOR(i, 0, n){
                        ans = max(ans, dp[1][i]);
                }

                cout << ans;
        }
}

signed main(){ quickly
        if(fopen(FILE".inp", "r")){
                freopen(FILE".inp", "r", stdin);
                freopen(FILE".out", "w", stdout);
        }

        cin >> n >> k;

        FOR(i, 2, n){
                int x; cin >> x;
                g[x + 1].push_back(i);
        }

        if(k > n){
                cout << 1;
        }
        else if(n <= 1005){
                SubtaskSQRT::solve();
        }
}

Compilation message (stderr)

catinatree.cpp: In function 'int main()':
catinatree.cpp:96:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |                 freopen(FILE".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:97:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |                 freopen(FILE".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
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