1 files changed, 161 insertions, 0 deletions
diff --git a/18/open/plat/sort.cpp b/18/open/plat/sort.cpp
new file mode 100644
index 0000000..8e7a49a
--- /dev/null
+++ b/18/open/plat/sort.cpp
@@ -0,0 +1,161 @@
+#include <algorithm>
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include <queue>
+#include <set>
+#include <map>
+#include <unordered_set>
+#include <unordered_map>
+#include <cmath>
+#include <cstring>
+#define init_io(pname) ifstream cin((string)pname+".in"); ofstream cout((string)pname+".out"); ios_base::sync_with_stdio(false); cin.tie(NULL)
+#define FOR(i, a, b, in) for (int i = (a); i < (b); i += in)
+#define REP(i, a, b) for (int i = (a); i < (b); i++)
+#define RFOR(i, a, b, in) for (int i = (a) - 1; i >= (b); i -= in)
+#define RREP(i, a, b) for (int i = (a) - 1; i >= (b); i--)
+#define trav(a, x) for (auto& a : x)
+#define mp make_pair
+#define pb push_back
+#define f first
+#define s second
+#define lb lower_bound
+#define ub upper_bound
+#define sz(x) (int)x.size()
+#define all(x) begin(x), end(x)
+#define rsz resize
+#define mem(a, b) memset(a, (b), sizeof(a))
+using namespace std;
+typedef string str;
+typedef long long ll;
+typedef long double ld;
+typedef pair<int, int> ii; typedef pair<ll, ll> pl; typedef pair<ld, ld> pd;
+typedef vector<int> vi; typedef vector<ll> vl; typedef vector<ld> vd;
+typedef vector<ii> vii; typedef vector<pl> vpl; typedef vector<pd> vpd;
+constexpr auto INF = (int)1e9;
+constexpr auto LINF = (ll)1e18;
+
+template<typename T> class fenwick_tree {
+private: vector<T> FT;
+public:
+	fenwick_tree(int N) { FT.assign(N + 1, 0); }
+	void clear() { FT.assign(FT.size(), 0); }
+	void update(int x, T val) { if (x > 0) for (; x < FT.size(); x += x & -x) FT[x] += val; }
+	T query(int x) { T ret = 0; if (x > 0) for (; x > 0; x -= x & -x) ret += FT[x]; return ret; }
+	T query(int x, int y) { return query(y) - (x == 1 ? 0 : query(x - 1)); }
+};
+
+template< typename T > class seg_tree {
+private:
+	int N;
+	vector<T> seg, tmp;
+public:
+	seg_tree(int size) {
+		N = size;
+		seg.resize(4 * N, 0);
+		tmp.resize(4 * N, 0);
+	}
+	seg_tree(int size, T A[]) {
+		N = size;
+		seg.resize(4 * N);
+		tmp.resize(4 * N);
+		build(A);
+	}
+	seg_tree(vector<T>& A) {
+		N = A.size();
+		seg.resize(4 * N);
+		tmp.resize(4 * N);
+		build(A);
+	}
+	void clear() { seg.assign(4 * N, 0); }
+	void pull(int n) { seg[n] = max(seg[n << 1], seg[n << 1 | 1]); }
+	void push(int l, int r, int n) {
+		seg[n] += tmp[n];
+		if (l != r) tmp[n << 1] += tmp[n], tmp[n << 1 | 1] += tmp[n];
+		tmp[n] = 0;
+	}
+	void build(T A[], int l = 0, int r = -1, int n = 1) {
+		if (r == -1) r = N - 1;
+		if (l == r) seg[n] = A[l];
+		else {
+			int m = (l + r) >> 1;
+			build(A, l, m, n << 1), build(A, m + 1, r, n << 1 | 1);
+			pull(n);
+		}
+	}
+	void build(vector<T>& A, int l = 0, int r = -1, int n = 1) {
+		if (r == -1) r = N - 1;
+		if (l == r) seg[n] = A[l];
+		else {
+			int m = (l + r) >> 1;
+			build(A, l, m, n << 1);
+			build(A, m + 1, r, n << 1 | 1);
+			pull(n);
+		}
+	}
+	void update(int x, T v, int l = 0, int r = -1, int n = 1) {
+		if (r == -1) r = N - 1;
+		if (l == r) seg[n] += v;
+		else {
+			int m = (l + r) >> 1;
+			x <= m ? update(x, v, l, m, n << 1) : update(x, v, m + 1, r, n << 1 | 1);
+			pull(n);
+		}
+	}
+	void update_range(int a, int b, T v, int l = 0, int r = -1, int n = 1) {
+		if (r == -1) r = N - 1;
+		push(n, l, r);
+		if (l > b || r < a) return;
+		if (l >= a && r <= b) {
+			tmp[n] = v;
+			push(n, l, r);
+		}
+		else {
+			int m = (l + r) >> 1;
+			update_range(a, b, v, l, m, n << 1), update_range(a, b, v, m + 1, r, n << 1 | 1);
+			pull(n);
+		}
+	}
+	T query(int a, int b, int l = 0, int r = -1, int n = 1) {
+		if (r == -1) r = N - 1;
+		if (l > b || r < a) return 0;
+		push(n, l, r);
+		if (l >= a && r <= b) return seg[n];
+		int m = (l + r) >> 1;
+		return max(query(a, b, l, m, n << 1), query(a, b, m + 1, r, n << 1 | 1));
+	}
+};
+
+int A[100005], C[100005] = { 0 };
+
+int main() {
+	init_io("sort");
+
+	int N;
+	cin >> N;
+	for (int i = 0; i < N; i++) cin >> A[i];
+	vector<ii> tmp;
+	for (int i = 0; i < N; i++) tmp.emplace_back(A[i], i);
+	sort(tmp.begin(), tmp.end());
+	for (int i = 0; i < N; i++) A[tmp[i].second] = i;
+
+	ll ans = 0;
+	fenwick_tree<int> FT(N);
+	seg_tree<int> seg(N);
+	for (int i = 0; i < N; i++) {
+		ans += FT.query(A[i], N - 1);
+		FT.update(A[i], 1);
+	}
+	for (int i = 0; i < N; i++) seg.update(A[i], i);
+	for (int i = 0; i < N; i++) {
+		int q = seg.query(0, A[i]);
+		if (i != q) C[i]++, C[q]--, ans++;
+	}
+	FT.clear();
+	for (int i = N - 1; i >= 0; i--) {
+		ans += (ll)C[i] * FT.query(A[i], N - 1);
+		FT.update(A[i], 1);
+	}
+	cout << (ans ? ans : N) << endl;
+}