1 files changed, 14 insertions, 0 deletions
diff --git a/math/kthperm.cpp b/math/kthperm.cpp
new file mode 100644
index 0000000..899dff1
--- /dev/null
+++ b/math/kthperm.cpp
@@ -0,0 +1,14 @@
+vector<ll> kthperm(ll k, ll n) {
+	Tree<ll> t;
+	vector<ll> res(n);
+	for (ll i = 1; i <= n; k /= i, i++) {
+		t.insert(i - 1);
+		res[n - i] = k % i;
+	}
+	for (ll& x : res) {
+		auto it = t.find_by_order(x);
+		x = *it;
+		t.erase(it);
+	}
+	return res;
+}