Tiger's leetcode solution

 Q: Write a function that takes the binary representation of a positive integer and returns the number of  set bits  it has (also known as t...

Q: Given an integer  n , return  the least number of perfect square numbers that sum to   n . A  perfect square  is an integer that is the s...

Given two strings  needle  and  haystack , return the index of the first occurrence of  needle  in  haystack , or  -1  if  needle  is not pa...

Given the  head  of a singly linked list, return  true  if it is a  palindrome  or  false  otherwise .   Example 1: Input: head = [1,2,2,1]...