Submission #639221

#	Time	Username	Problem	Language	Result	Execution time	Memory
639221		BackNoob	Cat in a tree (BOI17_catinatree)	C++14	51 / 100	669 ms	524288 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 = 2e5 + 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 sub[mxN];
int depth[mxN];
int sufmaxroot[mxN];
int sufmaxchild[mxN];
vector<int> dp[mxN];
vector<int> adj[mxN];
int res = 0;

void dfs(int u, int p)
{
    dp[u].resize(1);
    dp[u][0] = 1;
    maximize(res, 1);
    for(int v : adj[u]) {
        if(v == p) continue;
        dfs(v, u);

        vector<int> upd(max(depth[u], depth[v] + 1) + 227, 0);
        for(int j = depth[v]; j >= 0; j--) maximize(upd[j + 1], dp[v][j]);
        for(int i = depth[u]; i >= 0; i--) maximize(upd[i], dp[u][i]);

        sufmaxroot[depth[u]] = dp[u][depth[u]];
        for(int i = depth[u] - 1; i >= 0; i--) sufmaxroot[i] = max(sufmaxroot[i + 1], dp[u][i]);
        sufmaxchild[depth[v]] = dp[v][depth[v]];
        for(int i = depth[v] - 1; i >= 0; i--) sufmaxchild[i] = max(sufmaxchild[i + 1], dp[v][i]);

        for(int i = 0; i <= depth[u]; i++) {
            int j = max(i - 1, k - i - 1);
            if(j <= depth[v]) maximize(upd[i], dp[u][i] + sufmaxchild[j]);
        }

        for(int i = 0; i <= depth[v]; i++) {
            int j = max(i + 1, k - i - 1);
            if(j <= depth[u]) maximize(upd[i + 1], dp[v][i] + sufmaxroot[j]);
        }

        /*
        for(int i = depth[u]; i >= 0; i--) {
            for(int j = depth[v]; j >= 0; j--) {
                if(i + j + 1 >= k)
                    maximize(upd[min(i, j + 1)], dp[u][i] + dp[v][j]);
            }
        }
        */

        maximize(depth[u], depth[v] + 1);
        swap(dp[u], upd);
        //for(int i = 0; i <= depth[u]; i++) dp[u][i] = upd[i];
    }
}

// i
// i + j + 1 > k
// j > k - i - 1
//


// f[u][i] =

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

    dfs(1, -1);

    for(int i = 0; i <= depth[1]; i++) maximize(res, dp[1][i]);
    cout << res;


}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);


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

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