Submission #253201

#	Time	Username	Problem	Language	Result	Execution time	Memory
253201		aviroop123	Cat in a tree (BOI17_catinatree)	C++14	0 / 100	1 ms	384 KiB

catinatree

// #pragma comment(linker, "/stack:200000000")
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") // codeforces
//#pragma GCC target("avx,avx2,fma")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native") // yandex

#include "bits/stdc++.h"
using namespace std;
#ifndef LOCAL
#define endl '\n'
#endif

#define fr(i, a, b) for(int i = a; i <= b; i++)
#define rf(i, a, b) for(int i = a; i >= b; i--)
#define pf push_front
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
#define lb lower_bound
#define ub upper_bound

typedef long long ll;
typedef long double f80;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

int pct(int x) { return __builtin_popcount(x); }
int pct(ll x) { return __builtin_popcountll(x); }
int bt(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))
int bt(ll x) { return 63 - __builtin_clzll(x); } // floor(log2(x))
int cdiv(int a, int b) { return a / b + !(a < 0 || a % b == 0); }
ll cdiv(ll a, ll b) { return a / b + !(a < 0 || a % b == 0); }
int nxt_C(int x) { int c = x & -x, r = x + c; return (((r ^ x) >> 2) / c) | r; }
ll nxt_C(ll x) { ll c = x & -x, r = x + c; return (((r ^ x) >> 2) / c) | r; }

vector<int> get_bits(int mask) {
	vector<int> bb;
	while(mask) { int b = bt(mask); bb.pb(b); mask ^= (1 << b); }
	reverse(all(bb));
	return bb;
}

int get_mask(vector<int> v) {
	int mask = 0;
	for(int x : v) { mask ^= (1 << x); }
	return mask;
}

template<typename T>
void uniq(vector<T> &v) { sort(all(v)); v.resize(unique(all(v)) - v.begin()); }

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

ll rand(ll l, ll r){
	uniform_int_distribution<ll> uid(l, r);
	return uid(rng);
}

void sc() {}

template <typename Head, typename... Tail>
void sc(Head &H, Tail &... T) { cin >> H; sc(T...); }

#ifdef LOCAL
#define debug(...) cerr << "[L:" << __LINE__ << "][" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

// #ifndef LOCAL
// string to_string(__int128 x) {
// 	string s = "";
// 	bool neg = 0;
// 	if(x < 0) { s += "-"; neg = 1; x = -x; }
// 	if(!x) s += '0';
// 	while(x) {
// 		int rem = x % 10;
// 		s += to_string(rem);
// 		x /= 10;
// 	}
// 	reverse(s.begin() + neg, s.end());
// 	return s;
// }
// #endif

const int mod = 1e9 + 7; // 998244353;

int pwr(int a,ll b) {
	int ans = 1;
	while(b) {
		if(b & 1) ans = (ans * 1LL * a) % mod;
		a = (a * 1LL * a) % mod;
		b >>= 1;
	}
	return ans;
}

/*
	Lookout for overflows!!
	Check array sizes!!
	Clear before test cases!!
	Use the correct modulo!!
	Check for corner cases!!
	Are you forgetting something?!
	Read problem statement carefully!!!
*/

const int N = 1505;
int dp[N][N];
int sz[N];
int dp1[N];
int n, d;
vector<int> g[N];

void pre(int u,int p) {
    sz[u] = 1;
    vector<pii> nv;
    for(int v : g[u]) {
        if(v != p) {
            pre(v, u);
            nv.pb({sz[v], v});
        }
    }
    sort(all(nv));
    reverse(all(nv));
    g[u].clear();
    for(auto x : nv) {
        g[u].pb(x.se);
    }
}

void dfs(int u,int p) {
    sz[u] = 1;
    fr(i, 0, n) {
        dp[u][i] = 0;
    }
    dp[u][0] = 1;
    for(int v : g[u]) {
        if(v != p) {
            dfs(v, u);
            fr(i, 0, sz[v] + 1) {
                dp1[i] = 0;
            }
            // take something from u and v
            // for(int j = 0; j <= sz[v]; j++) {
            //     for(int i = max(0, d - j - 1); i <= sz[u]; i++) {
            //         int k = min(i, j + 1);
            //         dp1[k] = max(dp1[k], dp[u][i] + dp[v][j]);
            //     }
            // }
            for(int i = 0; i <= sz[v] + 1; i++) {
                int j = d - i - 1;
                if(j <= sz[v] && j >= 0) {
                    dp1[min(i, j + 1)] = max(dp1[min(i, j + 1)], dp[u][i] + dp[v][j]);
                }
            }
            for(int j = 0; j <= sz[v]; j++) {
                int i = d - (j + 1);
                if(i <= sz[u] && i >= 0) {
                    dp1[min(i, j + 1)] = max(dp1[min(i, j + 1)], dp[u][i] + dp[v][j]);
                }
            }
            fr(i, 0, sz[v]) { // take everything from v
                dp1[i + 1] = max(dp1[i + 1], dp[v][i]);
            }
            sz[u] += sz[v];
            fr(i, 0, sz[v] + 1) {
                dp[u][i] = max(dp[u][i], dp1[i]);
                dp[u][i] = max(dp[u][i], dp[u][i + 1]);
            }
        }
    }
}

void solve() {
    sc(n, d);
    fr(i, 2, n) {
        int p;
        sc(p);
        p++;
        g[i].pb(p);
        g[p].pb(i);
    }
    pre(1, 0);
    dfs(1, 0);
    int ans = 0;
    fr(i, 0, n) {
        ans = max(ans, dp[1][i]);
    }
    cout << ans;
}

int main() {
	ios :: sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int t = 1;
	// cin >> t;
	for(int tt = 1; tt <= t; tt++) {
		solve();
	}
	return 0;
}

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