### Goog phone interview

Software Engineer

Google

Full-time

1. Given a big of characters, generate all kinds of permutation with length==k.

e.g: bag: {a:2, b:1}, k=2 -> {aa, ab, ba}

follow up: in the above case: ab and ba are considered as duplicated.

e.g:bag: {a:2, b:1}, k=2 -> {aa, ab}

2. Ask me to design sth like “Big Integer” in JAVA.

Finally, turn out to be “String Multiply”: Given two numbers represented as strings, return multiplication of the numbers as a string.

e.g: bag: {a:2, b:1}, k=2 -> {aa, ab, ba}

follow up: in the above case: ab and ba are considered as duplicated.

e.g:bag: {a:2, b:1}, k=2 -> {aa, ab}

2. Ask me to design sth like “Big Integer” in JAVA.

Finally, turn out to be “String Multiply”: Given two numbers represented as strings, return multiplication of the numbers as a string.