Complete 3 problems: MergeSortedArray, RemoveDuplicatesFromSortedArray, RemoveElement;
Refactor codes in DataStructure;
Complete SortColors, i.e. array full of 0s, 1s, 2s, this is actually varietal Insertion-Sort only with given kinds of numbers;
GrayCode is not finished;
Complete 2 problems: LinkedListCycleDetection, RemoveDuplicatesFromSortedArray;
TODO: RemoveDuplicatesFromSortedListII;