Hired in GUIDED STUDY / 31 LESSONS
Coding patterns
Recognize the pattern, explain it, and solve it step by step.
Lessons
Sliding Window
Most people solve this interview question the slow way.
Binary Search
Find one number in a billion in 30 guesses.
Two Sum
The most asked coding interview question ever.
Hash Map
The one trick behind half of all interview questions.
Two Pointers
Two fingers beat two loops.
Dynamic Programming
DP is just remembering answers.
BFS vs DFS
Two ways to escape a maze.
Heap and Top K
Find the top 10 without sorting a million.
Intervals
Merge overlapping meetings in one pass.
Prefix Sums
Answer any range sum instantly.
Backtracking
Every combination, without the chaos.
Tries
How does autocomplete find words so fast?
Monotonic Stack
The next greater element trick, in one pass.
Tree Traversals
Three orders, one line moved.
Union-Find
Are these two people connected?
Valid Parentheses
A stack solves this in one pass.
Reverse a Linked List
Three pointers. One loop. Zero panic.
Longest Substring Without Repeats
The window that jumps when it breaks.
Number of Islands
Count the islands with one flood fill.
Best Time to Buy and Sell Stock
Buy low, sell high, in one pass.
LRU Cache
The cache every senior interview asks for.
Detect a Cycle
The tortoise and the hare finds a loop in a linked list.
Maximum Subarray
Keep it or start over.
Group Anagrams
Sort the letters, find the family.
Product Except Self
Do it without division.
Merge Two Sorted Lists
The zipper merge. Two sorted lists, zipped into one.
Turn constraints into an algorithm
100,000 IDs. Is any ID repeated?
Find the minimum ship capacity
Four boxes, two days. Find the smallest capacity that works.
Find the shortest maze path
The shortest maze path is the first one breadth-first search finds.
Count subarrays that sum to K
Count all nonempty slices with a target sum, even with negative numbers.
Schedule courses with prerequisites
Find a valid course order with a queue, or detect a cycle.