Author Archives: Hieu Nguyen

About Hieu Nguyen

I am a Senior member of technical staff (Oracle, eBay, Microsoft) and a founder of iNest, LLC (an IoT company)

System Design Tools and Templates

Tools Visual paradigm Lucid chart 2. Templates Problem Statement Scope Design Goals Assumptions High Level Design Challenges Open Items References

Posted in system design | Comments Off on System Design Tools and Templates

Interview Resources

Pramp BigOCheatSheet Hackerrank Grokking the system design interview Cracking the coding interview Leetcode

Posted in resources | Comments Off on Interview Resources

common git problems

Delete the remote branch git push -d origin <branch_name> Delete the local branch git branch -D <branch_name> Merge master into feature branch git checkout master git pull git checkout feature git merge master Checkout from a specific commit Use git checkout … Continue reading

Posted in git | Comments Off on common git problems


public class LengthOfLongestSubstring { public static int lengthOfLongestSubstring(String s) { if (s == null) { return 0; } Map<Character, Integer> map = new HashMap<>(); int maxLength = 0; int start = 0; for (int i = 0; i < s.length(); … Continue reading

Posted in hashtable | Comments Off on longest-substring-without-duplicate-characters


public class SortedSquare { public static int[] sortedSquare(int[] nums) { int[] result = new int[nums.length]; int writeIndex = nums.length – 1; int l = 0, r = nums.length – 1; while (l <= r) { if (nums[l] * nums[l] < … Continue reading

Posted in sorting | Comments Off on sorted-square


package; import; public class SumOfLeftLeaves { public static int sumOfLeftLeaves(TreeNode root) { // base case if (root == null) { return 0; } // left child is a leaf node if (root.left != null && root.left.left == null … Continue reading

Posted in recursion | Comments Off on sum-of-left-leaves


LeetCode link: Java Solution

Posted in singly-linked list | Comments Off on remove-nth-node-from-end-of-list