結果
問題 | No.742 にゃんにゃんにゃん 猫の挨拶 |
ユーザー |
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提出日時 | 2021-02-25 11:59:26 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 12 ms / 2,500 ms |
コード長 | 2,911 bytes |
コンパイル時間 | 1,900 ms |
コンパイル使用メモリ | 204,388 KB |
最終ジャッジ日時 | 2025-01-19 04:26:39 |
ジャッジサーバーID (参考情報) |
judge3 / judge5 |
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ファイルパターン | 結果 |
---|---|
other | AC * 16 |
コンパイルメッセージ
main.cpp: In function ‘int main()’: main.cpp:74:24: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 74 | REP(i, N) scanf("%d", &M[i]), --M[i]; | ~~~~~^~~~~~~~~~~~~
ソースコード
#include <bits/stdc++.h>using namespace std;#define FOR(i,a,b) for(int i=(a);i<(b);++i)#define REP(i,n) FOR(i,0,n)#define ALL(v) begin(v),end(v)template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }using ll = long long;using pii = pair<int, int>;constexpr ll INF = 1ll<<30;constexpr ll longINF = 1ll<<60;constexpr ll MOD = 1000000007;constexpr bool debug = false;//---------------------------------///*** @brief https://tkmst201.github.io/Library/DataStructure/BinaryIndexedTree.hpp*/template<typename T>struct BinaryIndexedTree {using value_type = T;using const_reference = const value_type &;using F = std::function<value_type (const_reference, const_reference)>;using size_type = std::size_t;private:size_type n;F f;value_type id_elem;std::vector<value_type> node;public:BinaryIndexedTree(size_type n, const F & f, const_reference id_elem): n(n), f(f), id_elem(id_elem), node(n + 1, id_elem) {}size_type size() const noexcept {return n;}void add(size_type i, const_reference x) {assert(i < size());++i;for (; i <= size(); i += i & -i) node[i] = f(node[i], x);}value_type sum(size_type i) const {assert(i <= size());value_type res = id_elem;for (; i > 0; i -= i & -i) res = f(node[i], res);return res;}size_type lower_bound(const_reference x) const {size_type res = 0;size_type s = id_elem, w = 1;while (w < size()) w <<= 1;for (; w > 0; w >>= 1) {if (res + w <= size()) {value_type cur = f(s, node[res + w]);if (cur < x) {res += w;s = cur;}}}return res;}};int main() {int N;cin >> N;vector<int> M(N);REP(i, N) scanf("%d", &M[i]), --M[i];ll ans = 0, ansiso = 0;REP(t, 2) {// -> countvector<int> isosum(N + 1);REP(i, N) {if (i == M[i]) ++isosum[i + 1];isosum[i + 1] += isosum[i];}BinaryIndexedTree<int> bit(N, [](int x, int y) { return x + y; }, 0);vector<int> evf(N), ev(N); // cnt, sumREP(i, N) {if (evf[i]) ans += bit.sum(i) - ev[i];if (i < M[i]) {const int cur = bit.sum(M[i]);ans += bit.sum(N) - cur;bit.add(M[i], 1);evf[M[i]] = true;ev[M[i]] = cur;ansiso += isosum[M[i] + 1] - isosum[i];}}vector<int> mp(N);REP(i, N) mp[M[i]] = i;bit = BinaryIndexedTree<int>(N, [](int x, int y) { return x + y; }, 0);vector<int> sum(N + 1);FOR(i, 1, N + 1) sum[i] = sum[i - 1] + (M[i - 1] < i - 1);for (int i = N - 1; i >= 0; --i) {if (M[i] < i) bit.add(M[i], 1);if (mp[i] < i) {ans += bit.sum(i + 1);ans += sum[i] - sum[mp[i]];}}REP(i, N) M[i] = N - 1 - M[i];reverse(ALL(M));}ans = ans / 2 + ansiso;cout << ans << endl;}