From 5ab8a5088b729a9953b8dff1b2a985dc8fb2098b Mon Sep 17 00:00:00 2001
From: mzuenni <michi.zuendorf@gmail.com>
Date: Mon, 27 Jun 2022 17:19:28 +0200
Subject: updated tcr

---
 math/transforms/xorTransform.cpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 math/transforms/xorTransform.cpp

(limited to 'math/transforms/xorTransform.cpp')

diff --git a/math/transforms/xorTransform.cpp b/math/transforms/xorTransform.cpp
new file mode 100644
index 0000000..48e4df2
--- /dev/null
+++ b/math/transforms/xorTransform.cpp
@@ -0,0 +1,17 @@
+void fft(vector<ll>& a, bool inverse = 0) {
+	int n = sz(a);
+	for (int i = 0, j = 1; j < n - 1; ++j) {
+		for (int k = n >> 1; k > (i ^= k); k >>= 1);
+		if (j < i) swap(a[i], a[j]);
+	}
+	for (int s = 1; s < n; s *= 2) {
+		for (int j = 0; j < n; j+= 2 * s) {
+			for (int k = 0; k < s; k++) {
+				ll u = a[j + k], t = a[j + s + k];
+				a[j + k] = u + t;
+				a[j + s + k] = u - t;
+	}}}
+	if (inverse) {
+		for (ll i = 0; i < n; i++) {
+			a[i] /= n;
+}}}
-- 
cgit v1.2.3