Count valid unset bits in numbers from 1 to n in python
Python program for Count valid unset bits in numbers from 1 to n. Here more solutions.
import math
# Python 3 program for
# Count valid unset bits in all numbers from 1 to n
class BitCount :
# Returns number of set bits of given number
def countSetBit(self, num) :
x = num
x = x - ((x >> 1) & 1431655765)
x = (x & 858993459) + ((x >> 2) & 858993459)
x = (x + (x >> 4)) & 252645135
x = x + (x >> 8)
x = x + (x >> 16)
x = x & 63
# Number of set bit
return x
# Handles the request of count the all
# unset bits from (1 to n)
def countUnsetBit(self, n) :
result = 0
# Execute loop from 1 to n
i = 1
while (i <= n) :
# Total bits - Active bits
result += (int((math.log(i) / math.log(2.0) + 1.0))) - \
self.countSetBit(i)
i += 1
# Display result
print(" Unset bits from (1 to",n,") :",result)
def main() :
task = BitCount()
# Test A
# number(1-7) Un-setbit
# ----------------
# 1 = 1 0
# 2 = 10 1
# 3 = 11 0
# 4 = 100 2
# 5 = 101 1
# 6 = 110 1
# 7 = 111 0
# --------------------
# 5
task.countUnsetBit(7)
# Test B
# number(1-10) Setbit
# ----------------
# 1 = 1 0
# 2 = 10 1
# 3 = 11 0
# 4 = 100 2
# 5 = 101 1
# 6 = 110 1
# 7 = 111 0
# 8 = 1000 3
# 9 = 1001 2
# 10 = 1010 2
# --------------------
# 12
task.countUnsetBit(10)
if __name__=="__main__":
main()
Output
Unset bits from (1 to 7 ) : 5
Unset bits from (1 to 10 ) : 12
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