Spring - Basic Concept
Spring has an object called the "Bean Factory". This factory creates new objects, or rather, new Beans for us, without the need of instantiating via the »
Longest Substring Without Repeating Characters
Problem Given a string, find the length of the longest substring without repeating characters. Example 1: Input: "abcabcbb" Output: 3 Explanation: The answer is "abc", with »
Perfect Squares
Problem Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n. Examples: Input: »
Unique Permutations
Problem Given a collection of numbers that might contain duplicates, return all possible unique permutations. Example: Input: [1,1,2] Output: [ [1,1,2], [1,2, »
Next Permutation
Problem Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possible, it must rearrange it as »