150 Problems — Visually Explained

Finally See How
Algorithms Actually Work.

Every DSA problem broken down step by step with interactive walkthroughs, real analogies, and execution you can actually follow. No memorization. Just clarity.

two_sum.ts — Deetcodes
1
2
3
4
5
6
7
function twoSum(nums, target) {
const map = new Map();
for (let i = 0; i < nums.length; i++) {
const diff = target - nums[i];
if (map.has(diff)) return [map.get(diff), i];
map.set(nums[i], i);
}
Variables
i 0
diff —
Array
2
0
7
1
11
2
15
3
Hash Map
{ }
Target: 9
Found: 2 + 7 = 9
STEP-BY-STEP EXECUTION

Watch Every Line
Come to Life

Instead of reading static code and guessing what happens, you see it. Each line executes in front of you — variables update, pointers shift, data structures transform. You follow the logic like watching a story unfold.

1let left = 0, right = arr.length - 1;
2while (left < right) {
3 const sum = arr[left] + arr[right];
4 if (sum === target) return [left, right];
5 else if (sum < target) left++;
6 else right--;
7}
left 0
right 4
sum —
1
3
5
7
11
ORGANIZED BY PATTERN

Learn Patterns,
Not Just Problems

150 problems grouped by the patterns behind them — Sliding Window, Two Pointers, BFS, Dynamic Programming, and more. Learn a pattern once and recognize it everywhere.

Sliding Window 12 problems
Maximum Subarray Longest Substring Min Window Substring +9 more
Two Pointers 10 problems
Two Sum II Container With Water 3Sum +7 more
Trees & Graphs 22 problems
Invert Binary Tree Level Order Traversal Number of Islands +19 more
Dynamic Programming 18 problems
Climbing Stairs Coin Change Longest Increasing Subseq +15 more

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150 DSA problems explained visually. Join the waitlist for early access.