Add bitduplication

Ninjaclasher · Apr 11, 2019 · 5bff4d6 · 5bff4d6
1 parent 6f47ea3
commit 5bff4d6
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Showing 2 changed files with 16 additions and 1 deletion.
diff --git a/.gitignore b/.gitignore
@@ -1,3 +1,2 @@
 DMOJ/cerc2000h.py
 DMOJ/phantomc1.py
-DMOJ/bitduplication.cpp
diff --git a/DMOJ/bitduplication.cpp b/DMOJ/bitduplication.cpp
@@ -0,0 +1,16 @@
+unsigned long long tmp;
+
+unsigned long long duplicatebits(unsigned long long n)
+{
+    tmp = (n ^ (n >> 16)) & 0x00000000ffff0000;
+    n ^= (tmp ^ (tmp << 16));
+    tmp = (n ^ (n >> 8))  & 0x0000ff000000ff00;
+    n ^= (tmp ^ (tmp << 8));
+    tmp = (n ^ (n >> 4))  & 0x00f000f000f000f0;
+    n ^= (tmp ^ (tmp << 4));
+    tmp = (n ^ (n >> 2))  & 0x0c0c0c0c0c0c0c0c;
+    n ^= (tmp ^ (tmp << 2));
+    tmp = (n ^ (n >> 1))  & 0x2222222222222222;
+    n ^= (tmp ^ (tmp << 1));
+    return n | (n << 1);
+}