Submission #1092755

#	Time	Username	Problem	Language	Result	Execution time	Memory
1092755		anhthi	Cat in a tree (BOI17_catinatree)	C++14	100 / 100	39 ms	18724 KiB

catinatree

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define ll long long
#define mp(x, y) make_pair(x, y)
#define sz(v) ((int) (v).size())
#define all(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define BIT(x, y) (((x) >> (y)) & 1)
#define pb push_back
#define max_rng *max_element
#define min_rng *min_element
#define rep(i, n) for(int i = 1, _n = (n); i <= _n; ++i)
#define forn(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)

template <class X, class Y>
    inline bool maximize(X &x, Y y) {
        return (x < y ? x = y, true : false);
    }

template <class X, class Y>
    inline bool minimize(X &x, Y y) {
        return (x > y ? x = y, true : false);
    }

template <class X>
    inline void compress(vector<X> &a) {
        sort(all(a));
        a.resize(unique(all(a)) - a.begin());
    }

int ctz(ll x) { return __builtin_ctzll(x); }
int lg(ll x) { return 63 - __builtin_clzll(x); }
int popcount(ll x) { return __builtin_popcount(x); }

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) {
    return l + abs((ll) rng()) % (r - l + 1);
}

const ll oo = (ll) 1e17;
const int inf = (int) 1e9, mod = (int) 1e9 + 7;

const int mxn = 2e5 + 5, mxm = 2e2 + 5, base = 307, LOG = 20;

void add(int &x, int y) { x += y; if (x >= mod) x -= mod; }
void sub(int &x, int y) { x -= y; if (x < 0) x += mod; }

int n, q, k;
int a[mxn];

vector<int> g[mxn];

pair<int, int> f[mxn];

void dfs(int u, int p) {
    f[u] = {1, 0};
    for (int v : g[u]) if (v != p) {
        dfs(v, u);
        f[u].fi += f[v].fi;
        if (f[u].se + f[v].se + 1 < k) {
            f[u].fi--;
            maximize(f[u].se, f[v].se + 1);
        }
        else {
            minimize(f[u].se, f[v].se + 1);
        }
    }
}

int main(void) {
    // think what before starting to code
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    #define TASK "partner"
    if (fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    cin >> n >> k;
    forn(i, 2, n) {
        int p; cin >> p;
        p++;
        g[p].pb(i);
    }

    dfs(1, 0);

    cout << f[1].fi;

    return 0;
}

Compilation message (stderr)

catinatree.cpp: In function 'int main()':
catinatree.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
catinatree.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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