Count how many 1 in binary representation of a 32-bit integer.
Given a collection of intervals, merge all overlapping intervals.
Partition an integers array into odd number first and even number second.
Give an integer array，find the longest increasing continuous subsequence in this array.
The count-and-say sequence is the sequence of integers beginning as follows:
Given a string s consists of upper/lower-case alphabets and empty space characters
' ', return the length of last word in the string.
Given a string containing just the characters
']', determine if the input string is valid.
Write a method to replace all spaces in a string with %20. The string is given in a characters array, you can assume it has enough space for replacement and you are given the true length of the string.
Given a boolean 2D matrix, find the number of islands.