Watch the algorithm think.
Every solution is an execution-synced walkthrough: the data structure, the code, the variables, and the why of each step — all moving together under your control.
Problems
- #1 · Two Sum
EasyHashmap
- #3 · Longest Substring Without Repeating Characters
MediumSliding window
- #20 · Valid Parentheses
EasyStack
- #167 · Two Sum II - Input Array Is Sorted
MediumTwo pointers
- #322 · Coin Change
MediumDynamic programming
- #560 · Subarray Sum Equals K
MediumPrefix sum + hashmap