Microsoft Interview Question for Software Engineer / Developers

Country: United States
Interview Type: Written Test

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7
of 9 vote

That's pretty simple. Each time you do X &= X-1 it erases the lowest non-zero bit. You repeat it and it removes one bit at a time, until all bits are gone. So that gives you the answer how many bits existed in the original integer.

For example, if the lowest bit is 1, after subtracting 1 it becomes 0. So AND the 1 bit and the 0 bit gives you 0, the bit is removed. All other bits are intact.

Next if you have the lowest bits as 100, subtracting 1 gives 011. AND them together, the lowest three bits cancel out. So that removes another lowest bit, with other bits intact.

Pretty useful trick to quickly count all bits without using if/else.

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6
of 6 vote

1) It will return number of 1s in the number.
eg: If input is 7 (0b0111) output will be 3
2) If the return value is 1, then it is a power of 2
eg: If input is 8 (0b1000) output will be 1

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4
of 4 vote

Counts the number of bits which are ON in a given inputted number .

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3
of 3 vote

x = 5

101 5
100 5-1
------
100 4
011 4-1
------
000 0

count of bit 1 == 2

---------------------------------
x = 10

1010 10
1001 10-1
------
1000 9
0111 9-1
------
0000 0

count of bit 1 == 2

---------------------------------

111010
111001
--------
111000
110111
--------
110000
101111
--------
100000
011111
--------
000000 0

count of bit 1 == 4

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0
of 0 vote

I think it is more like %. Do "i++" until the highest bit of the num is encountered. We get the rest of bits of the num.

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0

It counts the number of ones in the integer

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0
of 0 vote

this loop will be continue till max integer number

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0
of 0 vote

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0
of 0 vote

It is a fast algorithm to check whether a positive integer is a power of 2 or not. This works only if x>0.

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0
of 0 vote

Very nice trick to count 1 bites.

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0
of 0 vote

number of bits set in given number

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0
of 0 vote

No of bits set in the input

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0
of 0 vote

It returns number of set bits in a number. While counting you are also erasing that set bit.

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0
of 0 vote

1.It will return number of 1s in the number
2. i-1 had on advantage - least number to be subtracted from x to make it a power of 2

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0
of 0 vote

total count of set bits in the given number.

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0
of 0 vote

It gives number of SET bits of given number..

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