daifu

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {

daifu

/*
Given a collection of numbers that might contain duplicates, return all possible unique permutations.

For example,
[1,1,2] have the following unique permutations:
[1,1,2], [1,2,1], and [2,1,1].
*/
public class Solution {
    public boolean[] used;
    public ArrayList<ArrayList<Integer>> permuteUnique(int[] num) {

daifu

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {

daifu

/**
 * Given a sorted linked list, delete all duplicates such that each element appear only once.
    For example,
    Given 1->1->2, return 1->2.
    Given 1->1->2->3->3, return 1->2->3.
    
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;

daifu

/*
Given 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 
  [
    ["aa","b"],
    ["a","a","b"]

daifu

/*
Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.

An example is the root-to-leaf path 1->2->3 which represents the number 123.

Find the total sum of all root-to-leaf numbers.

For example,

    1

daifu

/*
Given an unsorted array of integers, find the length of the longest consecutive elements sequence.

For example,
Given [100, 4, 200, 1, 3, 2],
The longest consecutive elements sequence is [1, 2, 3, 4]. Return its length: 4.
*/

public class Solution {
    public int longestConsecutive(int[] num) {

daifu

/*
Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that:

Only one letter can be changed at a time
Each intermediate word must exist in the dictionary
For example,

Given:
start = "hit"
end = "cog"

daifu

/*
Given a collection of intervals, merge all overlapping intervals.

For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18]
*/

/**
 * Definition for an interval.

daifu

/*
Given a sorted integer array and a key, output its indices’ range.

For example,
[5, 7, 7, 8, 8, 10] –> Given 8, outputs [3, 4]
*/
public class Untitled {
    // get a range of position of sorted array
    public int[] getRange(int[] input, int target) {
        int upper = getUpperBound(input, target);