#612355 (C++17) No.778 クリスマスツリー

提出ソース

結果

問題	No.778 クリスマスツリー
ユーザー	minato
提出日時	2021-02-02 13:31:02
言語	C++17 (gcc 12.3.0 + boost 1.83.0)
結果	AC
実行時間	93 ms / 2,000 ms
コード長	6,414 bytes
コンパイル時間	2,104 ms
コンパイル使用メモリ	205,940 KB
実行使用メモリ	30,592 KB
最終ジャッジ日時	2024-06-29 23:40:19
合計ジャッジ時間	3,493 ms
ジャッジサーバーID （参考情報）	judge2 / judge4

このコードへのチャレンジ
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テストケース

テストケース表示

入力	結果	実行時間実行使用メモリ
testcase_00	AC	2 ms 5,248 KB
testcase_01	AC	2 ms 5,376 KB
testcase_02	AC	2 ms 5,376 KB
testcase_03	AC	2 ms 5,376 KB
testcase_04	AC	2 ms 5,376 KB
testcase_05	AC	2 ms 5,376 KB
testcase_06	AC	57 ms 30,592 KB
testcase_07	AC	25 ms 9,652 KB
testcase_08	AC	93 ms 19,584 KB
testcase_09	AC	86 ms 11,888 KB
testcase_10	AC	81 ms 11,768 KB
testcase_11	AC	77 ms 11,904 KB
testcase_12	AC	75 ms 11,904 KB
testcase_13	AC	41 ms 11,776 KB
testcase_14	AC	56 ms 30,592 KB

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ソースコード

raw source code

#include <bits/stdc++.h>
using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vector<T>>;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
constexpr char ln = '\n';
template <class Container> inline int SZ(const Container& v) { return int(v.size()); }
template <class T> inline void UNIQUE(vector<T>& v) { v.erase(unique(v.begin(), v.end()), v.end()); }
template <class T1, class T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return true; } return false; }
template <class T1, class T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return true; } return false; }
inline int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); }
inline int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); }
inline int popcount(ull x) { return __builtin_popcountll(x); }
inline int kthbit(ull x, int k) { return (x >> k) & 1; }
inline constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x - 1) * 10; }
const string YESNO[2] = {"NO", "YES"};
const string YesNo[2] = {"No", "Yes"};
inline void YES(bool t = true) { cout << YESNO[t] << "\n"; }
inline void Yes(bool t = true) { cout << YesNo[t] << "\n"; }
template <class T> inline void drop(T x) { cout << x << "\n"; exit(0); }
inline void print() { cout << "\n"; }
template <class T> inline void print(const vector<T>& v) { for (auto it = v.begin(); it != v.end(); ++it) { if (it != v.begin()) { cout << " "; } cout << *it; } print(); }
template <class T, class... Args> inline void print(const T& x, const Args& ... args) { cout << x << " "; print(args...); }
#ifdef MINATO_LOCAL
template <class T1, class T2> ostream& operator<<(ostream& os, pair<T1, T2> p) { return os << "(" << p.first << ", " << p.second << ")"; }
template <size_t N, class TUPLE> void debug_tuple(ostream& os, TUPLE _) { (void)os; (void)_; }
template <size_t N, class TUPLE, class T, class ...Args> void debug_tuple(ostream &os, TUPLE t) { os << (N == 0 ? "" : ", ") << get<N>(t); debug_tuple<N + 1, TUPLE, Args...>(os, t); }
template <class ...Args> ostream& operator<<(ostream& os, tuple<Args...> t) { os << "("; debug_tuple<0, tuple<Args...>, Args...>(os, t); return os << ")"; }
string debug_delim(int& i) { return i++ == 0 ? "" : ", "; }
#define debug_embrace(x) { int i = 0; os << "{";  { x } return os << "}"; }
template <class T> ostream& operator<<(ostream& os, vector<T> v) { debug_embrace( for (T e : v) { os << debug_delim(i) << e; } ) }
template <class T, size_t N> ostream& operator<<(ostream& os, array<T, N> a) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) }
template <class T, size_t N> enable_if_t<!is_same_v<char, remove_cv_t<T>>, ostream>& operator<<(ostream& os, T(&a)[N]) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) }
template <class Key> ostream& operator<<(ostream& os, set<Key> s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) }
template <class Key, class T> ostream& operator<<(ostream& os, map<Key, T> mp) { debug_embrace( for (auto e : mp) { os << debug_delim(i) << e; }) }
template <class Key> ostream& operator<<(ostream& os, multiset<Key> s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) }
template <class T> ostream& operator<<(ostream& os, queue<T> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.front(); } ) }
template <class T> ostream& operator<<(ostream& os, deque<T> q) { debug_embrace( for (T e : q) { os << debug_delim(i) << e; } ) }
template <class T> ostream& operator<<(ostream& os, priority_queue<T> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) }
template <class T> ostream& operator<<(ostream& os, priority_queue<T, vector<T>, greater<T>> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) }
void debug_out() { cerr << endl; }
template <class T, class... Args> void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); }
#define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__)
#else
#define debug(...) (void(0))
#endif
struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); cerr << fixed << setprecision(7); }; } fast_ios_;
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

template <class T>
struct BinaryIndexedTree {
  public:
    BinaryIndexedTree(){}
    BinaryIndexedTree(int n) : n_(n), data(n + 1,0) {}

    int size() const { return n_; }

    // (0-indexed) a[i] += x;
    void add(int i, T x) {
        assert(0 <= i and i < n_);
        for(++i; i <= n_; i += i & -i) data[i] += x;
    }

    // [l,r) (0-indexed) a[l] + …　+ a[r-1]
    T sum(int l, int r) const {
        if (l >= r) return T(0);
        assert(0 <= l and r <= n_);
        return sum(r) - sum(l);
    }

    // (0-indexed)
    // r = 0 or a[0] + a[1] + ... + a[r-1] < x
    // r = n or a[0] + a[1] + ... + a[r] >= x
    // a[0] + a[1] + ... + a[r] >= x となる最小の r を返す。
    int lowerbound(T x) const {
        int k = 1;
        int ret = 0;
        while ((k << 1) <= n_) k <<= 1;
        while (k > 0) {
            if (ret + k <= n_ and data[ret + k] < x) {
                x -= data[ret + k];
                ret += k;
            }
            k >>= 1;
        }
        return ret;
    }

    int upperbound(T x) const { return lowerbound(x + 1); }

  private:
    int n_;
    vector<T> data;

    // [0,k) (0-indexed) a[0] + … + a[i-1]
    T sum(int i) const {
        T ret = 0;
        for(; i > 0; i -= i & -i) ret += data[i];
        return ret;
    }
};

int main() {
    int N; cin >> N;
    vvec<int> G(N);
    rep(i,N-1) {
        int a; cin >> a;
        G[a].emplace_back(i+1);
    }

    ll ans = 0;
    BinaryIndexedTree<int> BIT(N);
    auto dfs=[&](auto self, int v)->void {
        ans += BIT.sum(0,v);
        BIT.add(v,1);
        for (int nv : G[v]) {
            self(self,nv);
        }
        BIT.add(v,-1);
    };
    dfs(dfs,0);
    cout << ans << ln;
}

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結果

テストケース

ソースコード