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Amazon Interview Question for SDE-2s


Country: India
Interview Type: Phone Interview



Comment hidden because of low score. Click to expand.
2
of 4 vote

Can't you just return 0 regardless of the input?

- chriscow January 26, 2014 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 votes

Ha, yeah...the problem as stated here might allow that, but that seems like an awfully weird interview question.

I was working off the assumption that you needed to take a number and actually mutate it to zero without doing a direct assignment...kind of like how in x86, when you want to zero out a register, you do "xor (reg), (reg)".

- Anonymous January 26, 2014 | Flag
Comment hidden because of low score. Click to expand.
0
of 0 votes

Then I would do this

return input & 0;

haha

- chriscow January 26, 2014 | Flag
Comment hidden because of low score. Click to expand.
0
of 0 votes

[Correct]
Input : 101011
Output : 000000

[Wrong]
Input : 101011
Output : 0

Then how you fix this.

- raghu February 11, 2014 | Flag
Comment hidden because of low score. Click to expand.
1
of 1 vote

Is anything wrong in either of following two?
1. number & 0;
2. number ^ number;

- Dharmendra January 26, 2014 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

XOR the number with itself.

You can do this in a language like Java or C# with a simple number ^ number;

The result of an XOR between two bits is only 1 when one, but not both, of the bits are 1.

Logically, you can see that if you XOR a number with itself, any 1 bits will go to zero because 1 ^ 1 = 0. Any bits that are 0 will stay zero, because 0 ^ 0 = 0. So any number XOR'd with itself is always 0.

- Anonymous January 26, 2014 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

Just calculate the number of set bits. These need to be flipped. I guess this would be a respectable answer.

- Nascent January 26, 2014 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

number & 0 is the expected answer

- Mahesh January 26, 2014 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

n & ~n

- Murali Mohan January 26, 2014 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

Just return 0. Don't care of any inputs.

- gourahari.das January 28, 2014 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

XOR and AND : if using XOR then first check if number = 1 then input[i] ^ 1;
if using AND then directly input[i] & 0;

- Sameer Shukla January 28, 2014 | Flag Reply


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