結果
問題 | No.1300 Sum of Inversions |
ユーザー |
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提出日時 | 2020-12-19 18:31:13 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 504 ms / 2,000 ms |
コード長 | 3,413 bytes |
コンパイル時間 | 3,118 ms |
コンパイル使用メモリ | 208,376 KB |
最終ジャッジ日時 | 2025-01-17 03:56:45 |
ジャッジサーバーID (参考情報) |
judge1 / judge3 |
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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>using namespace std;#define rep(i,n) for(int i = 0; i < (n); i++)typedef long long ll;typedef long double ld;typedef pair<int,int> P;constexpr int mod = 998244353;struct mint {ll x; // typedef long long ll;mint(ll x=0):x((x%mod+mod)%mod){}mint operator-() const { return mint(-x);}mint& operator+=(const mint a) {if ((x += a.x) >= mod) x -= mod;return *this;}mint& operator-=(const mint a) {if ((x += mod-a.x) >= mod) x -= mod;return *this;}mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}mint operator+(const mint a) const { return mint(*this) += a;}mint operator-(const mint a) const { return mint(*this) -= a;}mint operator*(const mint a) const { return mint(*this) *= a;}mint pow(ll t) const {if (!t) return 1;mint a = pow(t>>1);a *= a;if (t&1) a *= *this;return a;}// for prime modmint inv() const { return pow(mod-2);}mint& operator/=(const mint a) { return *this *= a.inv();}mint operator/(const mint a) const { return mint(*this) /= a;}};template <typename T>struct SegmentTree {int n;vector<T> node;T e;T f(T a, T b) {return (a + b);}void g(T &a, T b) {a += b;}SegmentTree (int sz, T init = 0) {n = 1; e = init; while (n < sz) n <<= 1;node.assign(2*n, init);for (int i = n - 2; i >= 0; i--) node[i] = f(node[2*i+1], node[2*i+2]);}void update(int k, T x) {k += (n - 1);g(node[k], x);while (k > 0) {k = (k - 1) >> 1;node[k] = f(node[2*k+1], node[2*k+2]);}}T query(int a, int b, int k = 0, int l = 0, int r = -1) {if (r < 0) r = n;if (r <= a || b <= l) return e;if (a <= l && r <= b) return node[k];T vl = query(a, b, 2*k+1, l, (l+r)/2);T vr = query(a, b, 2*k+2, (l+r)/2, r);return f(vl, vr);}T getvalue(int k) {return query(k,k+1);}template <typename F>int find (int a, int b, T x, F &ok, int k = 0, int l = 0, int r = -1) {if (r < 0) r = n;if (!ok(node[k]) || r <= a || b <= l) return b;if (k >= n - 1) return k - n + 1;int vl = find(a, b, x, ok, 2*k+1, l, (l + r)/2);if (vl != b) return vl;return find(a, b, x, ok, 2*k+2, (l + r)/2, r);}};int main() {int n;cin >> n;vector<int> a(n);rep(i,n) cin >> a[i];auto b = a;sort(b.begin(), b.end());b.erase(unique(b.begin(), b.end()), b.end());int m = b.size();vector<mint> lsum(n, 0), rsum(n, 0);vector<int> l(n), r(n);{SegmentTree<int> cnt(m, 0);SegmentTree<mint> sum(m, 0);for ( int i = 0; i < n; i++) {int j = lower_bound(b.begin(), b.end(), a[i]) - b.begin();sum.update(j, a[i]);cnt.update(j, 1);lsum[i] = sum.query(j + 1, m);l[i] = cnt.query(j + 1, m);}}{SegmentTree<int> cnt(m, 0);SegmentTree<mint> sum(m, 0);for (int i = n - 1; i >= 0; i--) {int j = lower_bound(b.begin(), b.end(), a[i]) - b.begin();sum.update(j, a[i]);cnt.update(j, 1);rsum[i] = sum.query(0, j);r[i] = cnt.query(0, j);}}mint res = 0;for (int i = 0; i < n; i++) {if (!l[i] * r[i]) continue;int j = lower_bound(b.begin(), b.end(), a[i]) - b.begin();mint aa = a[i];res += lsum[i] * r[i] + rsum[i] * l[i] + aa * l[i] * r[i];}cout << res.x << endl;return 0;}