結果

問題 No.742 にゃんにゃんにゃん　猫の挨拶
コンテスト
ユーザー ningenMe
提出日時 2020-04-28 05:42:32
言語 C++14
(gcc 13.3.0 + boost 1.89.0)
結果
AC  
実行時間 6 ms / 2,500 ms
コード長 4,840 bytes
記録
記録タグの例:
初AC ショートコード 純ショートコード 純主流ショートコード 最速実行時間
コンパイル時間 1,601 ms
コンパイル使用メモリ 170,924 KB
実行使用メモリ 5,248 KB
最終ジャッジ日時 2024-11-23 15:44:46
合計ジャッジ時間 2,447 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 16
権限があれば一括ダウンロードができます

ソースコード

diff #
raw source code 

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433L;

template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}


//Binary Indexed Tree
template<class Operator> class BinaryIndexedTree {
	Operator Op;                                         
	using typeNode = decltype(Op.unitNode);
	size_t depth;         
	size_t length;
	size_t num;
	vector<typeNode> node;

public:
	BinaryIndexedTree(const size_t num) : num(num) {
		for (depth = 1,length = 1; length < num; depth++,length *= 2);
		node.resize(length+1, Op.unitNode);
	}
 
	//[idx,idx+1) update
	void update(size_t idx, typeNode var) {
		assert(0 <= idx && idx < length);
		for (++idx; idx <= length; idx += idx & -idx) node[idx] = Op.funcNode(node[idx],var);
	}

	//[0,idx) get
	typeNode get(size_t idx) {
		typeNode ret = Op.unitNode;
		for (idx = min(length,idx); idx > 0; idx -= idx & -idx) ret = Op.funcNode(ret,node[idx]);
		return ret;
	}

	//return [0,length]
	int BinarySearch(typeNode var) {
		if(!Op.funcCheck(node.back(),var)) return num;
		typeNode ret = Op.unitNode;
		size_t off = 0;
		for(size_t idx = length; idx; idx >>= 1){
			if(off + idx <= length && !Op.funcCheck(Op.funcNode(ret,node[off+idx]),var)) {
				off += idx;
				ret = Op.funcNode(ret,node[off]);
			}
		}
		return min(off,num);
	}

	void print() {
		cout << "{ " << get(1);
		for(int i = 1; i < length; ++i) cout << ", " << get(i+1);
		cout << " }" << endl;
	}
};

template<class typeNode> struct NodePrefixSumPointAdd {
	typeNode unitNode = 0;
	typeNode funcNode(typeNode l,typeNode r){return l+r;}
	// Binary Search for first index where funcCheck is true
	bool funcCheck(typeNode nodeVal,typeNode val){return val <= nodeVal;}
};

template<class typeNode> struct nodeUpdatePrefixGCD {
	typeNode unitNode = 0;
	typeNode funcNode(typeNode l,typeNode r){return ((r == 0) ? l : funcNode(r, l % r));}
	// Binary Search for first index at where funcCheck is true
	bool funcCheck(typeNode nodeVal,typeNode var){return var == nodeVal;}
};

//verify https://atcoder.jp/contests/chokudai_S001/tasks/chokudai_S001_j
//verify https://atcoder.jp/contests/abc130/tasks/abc130_d

int main() {
    SPEED
    int N; cin >> N;
    vector<int> A(N+1,0);
    for(int i = 1; i <= N; ++i) {
        cin >> A[i];
    }
    BinaryIndexedTree<NodePrefixSumPointAdd<int>> bit(N+2);
    int ans = 0;
    for(int i = N; 1 <= i; --i) {
        ans += bit.get(A[i]);
        bit.update(A[i],1);
    }
    cout << ans << endl;
    return 0;
}
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