#include <iostream>
#include <vector>
using namespace std;
namespace {
using ll = long long;
struct Counter {
int inv = 999'999'999;
ll cnt = 0;
void update(Counter const& rhs)
{
if (rhs.inv < inv) *this = rhs;
else if (rhs.inv == inv) cnt += rhs.cnt;
}
};
void go(vector<int> const& perm, vector<Counter>& res, int i, int inv, vector<int>& cur)
{
int n = perm.size();
if (i == n) {
res[cur.size()].update({inv, 1});
return;
}
go(perm, res, i + 1, inv, cur);
int x = perm[i];
cur.emplace_back(x);
for (int y: cur) if (y > x) ++inv;
go(perm, res, i + 1, inv, cur);
cur.pop_back();
}
vector<Counter> solve(vector<int> const& perm)
{
int n = perm.size();
vector<Counter> res(n + 1);
res[0] = {0, 1};
vector<int> cur;
go(perm, res, 0, 0, cur);
return res;
}
}
int main()
{
iostream::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> perm(n);
for (auto& x: perm) {
cin >> x;
--x;
}
auto res = solve(perm);
for (int i = 1; i <= n; ++i) {
cout << res[i].inv << ' ' << res[i].cnt << '\n';
}
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 | #include <iostream> #include <vector> using namespace std; namespace { using ll = long long; struct Counter { int inv = 999'999'999; ll cnt = 0; void update(Counter const& rhs) { if (rhs.inv < inv) *this = rhs; else if (rhs.inv == inv) cnt += rhs.cnt; } }; void go(vector<int> const& perm, vector<Counter>& res, int i, int inv, vector<int>& cur) { int n = perm.size(); if (i == n) { res[cur.size()].update({inv, 1}); return; } go(perm, res, i + 1, inv, cur); int x = perm[i]; cur.emplace_back(x); for (int y: cur) if (y > x) ++inv; go(perm, res, i + 1, inv, cur); cur.pop_back(); } vector<Counter> solve(vector<int> const& perm) { int n = perm.size(); vector<Counter> res(n + 1); res[0] = {0, 1}; vector<int> cur; go(perm, res, 0, 0, cur); return res; } } int main() { iostream::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; vector<int> perm(n); for (auto& x: perm) { cin >> x; --x; } auto res = solve(perm); for (int i = 1; i <= n; ++i) { cout << res[i].inv << ' ' << res[i].cnt << '\n'; } return 0; } |
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