Submission #639439

#	Time	Username	Problem	Language	Result	Execution time	Memory
639439		BackNoob	Cat in a tree (BOI17_catinatree)	C++14	100 / 100	208 ms	163628 KiB

catinatree

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define endl '\n'
#define MASK(i) (1LL << (i))
#define ull unsigned long long
#define ld long double
#define pb push_back
#define all(x) (x).begin() , (x).end()
#define BIT(x , i) ((x >> (i)) & 1)
#define TASK "task"
#define sz(s) (int) (s).size()

using namespace std;
const int mxN = 3e5 + 227;
const int inf = 1e9 + 277;
const int mod = 1e9 + 7;
const ll infll = 1e18 + 7;
const int base = 307;
const int LOG = 20;

template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}

int n;
int k;
int a[mxN];
int res = 0;
vector<int> adj[mxN];

deque<ll> dfs(int u, int p)
{
    deque<ll> res;
    res.push_front(1);
    for(int v : adj[u]) {
        if(v == p) continue;
        deque<ll> add = dfs(v, u);
        add.push_front(add.front());
        if(sz(res) < sz(add)) swap(res, add);

        deque<ll> combined = add;
        for(int x = 0; x < sz(add); x++) {
            int y = max(x, k - x);
            if(y < sz(res))
                maximize(combined[x], add[x] + res[y]);
            if(y < sz(add))
                maximize(combined[x], res[x] + add[y]);
        }
        int maximum = 0;
        for(int i = sz(add) - 1; i >= 0; i--) {
            maximize(maximum, combined[i]);
            maximize(maximum, add[i]);
            maximize(res[i], maximum);
        }
    }

    return res;
}

// dp[u][i] = dp[u][i + 1]
// dp[u][min(i, j + 1)] = dp[u][i] + dp[v][j];
// dp[u][i] = dp[u][i] + sufchild[v][j]
// dp[u][j + 1] = sufroot[u][i] + dp[v][j + 1]

void solve()
{
    cin >> n >> k;
    //for(int i = 1; i <= n; i++) cin >> a[i];
    for(int u = 2; u <= n; u++) {
        int v;
        cin >> v;
      	++v;
        adj[u].pb(v);
        adj[v].pb(u);
    }

    deque<ll> res = dfs(1, -1);
    cout << res.front();
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    //freopen("task.inp", "r", stdin);

    int tc = 1;
    //cin >> tc;
    while(tc--) {
    	solve();
    }
    return 0;
}

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