wayetan

/**
 * Given 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 vertically neighboring. 
 * The same letter cell may not be used more than once.
 * For example,
 * Given board =
 * [
      ["ABCE"],
      ["SFCS"],
      ["ADEE"]

wayetan

/**
 * Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.
 * Above is a histogram where width of each bar is 1, given height = [2,1,5,6,2,3].
 * The largest rectangle is shown in the shaded area, which has area = 10 unit.
 * For example,
 * Given height = [2,1,5,6,2,3],
 * return 10.
 */
public class Solution {
    public int largestRectangleArea(int[] height) {

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/**
 * Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area.
 */
public class Solution {
    public int maximalRectangle(char[][] matrix) {
        int m = matrix.length;
        int n = m == 0 ? 0 : matrix[0].length;
        int[][] height = new int[m][n];
        int maxArea = 0;
        for(int i = 0; i < m; i++) {

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/**
 * Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that:
 * 1. Only one letter can be changed at a time
 * 2. Each intermediate word must exist in the dictionary
 * For example,
 * Given:
 * start = "hit"
 * end = "cog"
 * dict = ["hot","dot","dog","lot","log"]
 * As one shortest transformation is "hit" -> "hot" -> "dot" -> "dog" -> "cog",

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/**
 * Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.
 * Below is one possible representation of s1 = "great":
 * great
   /    \
  gr    eat
 / \    /  \
g   r  e   at
           / \
          a   t

wayetan

/** 
 * Validate if a given string is numeric.
 * Some examples:
 * "0" => true
 * " 0.1 " => true
 * "abc" => false
 * "1 a" => false
 * "2e10" => true
 * Note: It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one.
 */

wayetan

/**
 * A message containing letters from A-Z is being encoded to numbers using the following mapping:
 * 'A' -> 1
 * 'B' -> 2
 * ...
 * 'Z' -> 26
 * Given an encoded message containing digits, determine the total number of ways to decode it.
 * For example,
 * Given encoded message "12", it could be decoded as "AB" (1 2) or "L" (12).
 * The number of ways decoding "12" is 2.

wayetan

/**
 * Given a string containing only digits, restore it by returning all possible valid IP address combinations.
 * For example:
 * Given "25525511135",
 * return ["255.255.11.135", "255.255.111.35"]. (Order does not matter)
 */

public class Solution {
    public ArrayList<String> restoreIpAddresses(String s) {
        ArrayList<String> res = new ArrayList<String>();

wayetan

/**
 * Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.
 * For example,
 * Given:
 * s1 = "aabcc",
 * s2 = "dbbca",
 * When s3 = "aadbbcbcac", return true.
 * When s3 = "aadbbbaccc", return false.
 */
public class Solution {

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/**
 * Given a binary tree, find the maximum path sum.
 * The path may start and end at any node in the tree.
 * For example:
 * For example:
 *     1
      / \
     2   3
 * Return 6.
 */