DescriptionGiven two words (beginWord and endWord), and a dictionary, find the length of shortest transformation sequence from beginWord to endWord, such that: Only one letter can be changed at a tim

DescriptionGiven n, generate all structurally unique BST’s (binary search trees) that store values 1…n. For example,Given n = 3, your program should return all 5 unique BST’s shown below. 1

DescriptionGiven a string s, partition s such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of s. For example, given s = “aab”,Return [ [&quo

DescriptionGiven an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. The original problem is here. The original code is here.

DescriptionGiven a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where “adjacent” cells are those horizontally or ve

DescriptionTwo elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. The original problem is here. The original code is here.

DescriptionGiven a 2D board containing ‘X’ and ‘O’, capture all regions surrounded by ‘X’. A region is captured by flipping all ‘O’s into ‘X’s in that surrounded region. For example, X X X X X O O X X

DescriptionAll DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: “ACGAATTCCG”. When studying DNA, it is sometimes useful to identify repeated sequences within the

DescriptionGiven an unsorted array, find the maximum difference between the successive elements in its sorted form. Try to solve it in linear time/space. Return 0 if the array contains less than 2 ele

DescriptionGiven a 2D binary matrix filled with 0’s and 1’s, find the largest square containing all 1’s and return its area. For example, given the following matrix: 1 0 1 0 0 1 0 1 1 1 1 1 1 1 1 1 0