結果
問題 | No.1300 Sum of Inversions |
ユーザー |
|
提出日時 | 2024-09-01 11:00:41 |
言語 | C++23 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 1,758 ms / 2,000 ms |
コード長 | 2,411 bytes |
コンパイル時間 | 3,996 ms |
コンパイル使用メモリ | 288,520 KB |
実行使用メモリ | 94,536 KB |
最終ジャッジ日時 | 2024-09-01 11:01:29 |
合計ジャッジ時間 | 47,590 ms |
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 |
---|---|
sample | AC * 3 |
other | AC * 34 |
ソースコード
#include <bits/stdc++.h>#include <atcoder/fenwicktree>#include <atcoder/modint>using namespace std;using namespace atcoder;using ll = long long;using mint = modint998244353;template<typename S, typename T> struct CompressedBIT2D {private:int N;vector<fenwick_tree<T>> bit;vector<vector<S>> ys;vector<pair<S, S>> ps;int id(S x) const {return ranges::lower_bound(ps, make_pair(x, S()), [](const pair<S, S> &a, const pair<S, S> &b) { return a.first < b.first; }) - ps.begin();}int id(int i, S y) const { return ranges::lower_bound(ys[i], y) - ys[i].begin(); }public:CompressedBIT2D() = default;CompressedBIT2D(int N) { ps.reserve(N); }void use(S x, S y) { ps.emplace_back(x, y); }void build() {ranges::sort(ps);ps.erase(unique(ps.begin(), ps.end()), ps.end());N = ps.size();bit.resize(N + 1);ys.resize(N + 1);for(int i = 0; i <= N; ++i) {for(int j = i + 1; j <= N; j += j & -j) { ys[j].emplace_back(ps[i].second); }ranges::sort(ys[i]);ys[i].erase(unique(ys[i].begin(), ys[i].end()), ys[i].end());bit[i] = fenwick_tree<T>(ys[i].size() + 1);}}void add(S x, S y, T a) {int i = ranges::lower_bound(ps, make_pair(x, y)) - ps.begin();assert(ps[i] == make_pair(x, y));for(++i; i <= N; i += i & -i) { bit[i].add(id(i, y), a); }}T sum(S x, S y) {T r = T();for(int a = id(x); a; a -= a & -a) { r += bit[a].sum(0, id(a, y)); }return r;}T sum(S lx, S rx, S ly, S ry) {T r = T();int a = id(lx), b = id(rx);while(a != b) {if(a < b) {r += bit[b].sum(id(b, ly), id(b, ry));b -= b & -b;}else {r -= bit[a].sum(id(a, ly), id(a, ry));a -= a & -a;}}return r;}};int main() {ios::sync_with_stdio(false);cin.tie(nullptr);ll N;cin >> N;vector<ll> A(N);CompressedBIT2D<ll, mint> S, C;for(ll i = 0; i < N; i++) {cin >> A[i];S.use(i, A[i]);C.use(i, A[i]);}S.build();C.build();for(ll i = 0; i < N; i++) {S.add(i, A[i], A[i]);C.add(i, A[i], 1);}mint ans = 0;for(ll i = 0; i < N; i++) {mint ls = S.sum(0, i, A[i] + 1, 1e18), rs = S.sum(i + 1, N, 0, A[i]);mint lc = C.sum(0, i, A[i] + 1, 1e18), rc = C.sum(i + 1, N, 0, A[i]);ans += ls * rc + rs * lc + lc * rc * A[i];}cout << ans.val() << "\n";}