From f843a4acc9eab88ff4670b8cbb093e27771da2a9 Mon Sep 17 00:00:00 2001
From: Claudio Maggioni <claudio@maggioni.xyz>
Date: Thu, 4 Apr 2019 20:25:17 +0200
Subject: [PATCH] Added H solution
---
bit_difference.py | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/bit_difference.py b/bit_difference.py
index f6fe3f0..263660d 100644
--- a/bit_difference.py
+++ b/bit_difference.py
@@ -2,20 +2,16 @@
import sys
-def xor_count(a, b):
- xor = a ^ b
- i = 0
- while xor != 0:
- i = i + (xor & 1)
- xor = xor >> 1
- return i
-
-
def bitwise_difference(A):
+ l = len(A)
s = 0
- for i in range(len(A)):
- for j in range(i+1,len(A)):
- s = s + xor_count(A[i], A[j])
+ for i in range(32):
+ n1 = 0
+ for j in range(l):
+ n1 += A[j] & 1
+ A[j] = A[j] >> 1
+ n0 = l - n1
+ s += n1 * n0
return s