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Your friend is typing his name into a keyboard. Sometimes, when typing a character c, the key might ...

Given an array A of non-negative integers, half of the integers in A are odd, and half of the intege...

Given a string S, return the "reversed" string where all characters that are not a letter ...

In a deck of cards, each card has an integer written on it. Return true if and only if you can choos...

Given an array A of integers, for each integer A[i] we may choose any x with -K <= x <= K, and...