docs(docs): add study decks, new reference pages, and fix header image path

README.md

@@ -1,5 +1,5 @@
 <p align="center">
-  <img alt="header" src=".github/assets/dependency-spine.svg" />
+  <img alt="header" src=".public/dependency-spine.svg" />
 </p>
 
 <p align="center">

docs/02-concepts/01-arrays-and-strings.mdx

@@ -63,3 +63,9 @@ Random access in this context means that you can access an element at any index
 </Columns>
 
 
+
+## Study deck
+
+Drill the essentials — click the deck, then use the arrow keys.
+
+<StudyDeck deck="arrays-and-strings" />

docs/02-concepts/02-hashing.mdx

@@ -28,3 +28,9 @@ Appending to the end of a list is amortized O(1) time complexity. This means tha
 Random access in this context means that you can access an element at any index in constant time.
 :::
 
+
+## Study deck
+
+Drill the essentials — click the deck, then use the arrow keys.
+
+<StudyDeck deck="hashing" />

docs/02-concepts/03-binary-search.mdx

@@ -28,3 +28,9 @@ Appending to the end of a list is amortized O(1) time complexity. This means tha
 Random access in this context means that you can access an element at any index in constant time.
 :::
 
+
+## Study deck
+
+Drill the essentials — click the deck, then use the arrow keys.
+
+<StudyDeck deck="binary-search" />

docs/03-guides/02-two-pointers.mdx

@@ -12,3 +12,9 @@ This page is a scaffold. Notes, canonical problems, and template code are not wr
 
 
 
+
+## Study deck
+
+Drill the essentials — click the deck, then use the arrow keys.
+
+<StudyDeck deck="two-pointers" />

docs/03-guides/03-prefix-sum.mdx

@@ -6,3 +6,9 @@ description: 'Precomputed cumulative state for O(1) range queries.'
 :::warning[Under construction]
 This page is a scaffold. Notes, canonical problems, and template code are not written yet.
 :::
+
+## Study deck
+
+Drill the essentials — click the deck, then use the arrow keys.
+
+<StudyDeck deck="prefix-sum" />

docs/03-guides/04-sliding-window.mdx

@@ -6,3 +6,9 @@ description: 'Two pointers plus incremental state between them.'
 :::warning[Under construction]
 This page is a scaffold. Notes, canonical problems, and template code are not written yet.
 :::
+
+## Study deck
+
+Drill the essentials — click the deck, then use the arrow keys.
+
+<StudyDeck deck="sliding-window" />

docs/reference/01-reverse-string.mdx

@@ -0,0 +1,45 @@
+---
+title: '344. Reverse String'
+description: Write a function that reverses a string. The input string is given as an array of characters s
+sidebar:
+  badge: 'Easy'
+---
+
+<Badge variant="accent">Two Pointers</Badge>
+
+:::warning
+You must do this by modifying the input array in-place with O(1) extra memory.
+:::
+
+### Example 1:
+- Input: `s = ["h","e","l","l","o"]`
+- Output: `["o","l","l","e","h"]`
+
+### Example 2:
+- Input: `s = ["H","a","n","n","a","h"]`
+- Output: `["h","a","n","n","a","H"]`
+
+### Constraints:
+
+- `1 <= s.length <= 10^5`
+- `s[i]` is a printable ascii character.
+
+## Solution
+
+```js
+/**
+ * @param {character[]} s
+ * @return {void} Do not return anything, modify s in-place instead.
+ */
+
+var reverseString = function(s) {
+    let i = 0;
+    let j = s.length - 1;
+    
+    while (i < j) {
+        [s[i], s[j]] = [s[j], s[i]];
+        j--;
+        i++;
+    }   
+};
+```

docs/reference/02-squares-of-a-sorted-array.mdx

@@ -0,0 +1,54 @@
+---
+title: '977. Squares of a Sorted Array'
+description: Given an integer array nums sorted in non-decreasing order, return an array of the squares of each number sorted in non-decreasing order
+sidebar:
+  badge: 'Easy'
+---
+
+<Badge variant="accent">Two Pointers</Badge>
+
+::::warning
+Squaring each element and sorting the new array is very trivial, could you find an O(n) solution using a different approach?
+::::
+
+### Example 1:
+- Input: `nums = [-4,-1,0,3,10]`
+- Output: `[0,1,9,16,100]`
+- Explanation: After squaring, the array becomes `[16,1,0,9,100]`. After sorting, it becomes `[0,1,9,16,100]`.
+
+### Example 2:
+- Input: `nums = [-7,-3,2,3,11]`
+- Output: `[4,9,9,49,121]`
+
+### Constraints:
+
+- `1 <= nums.length <= 10^4`
+- `-10^4 <= nums[i] <= 10^4`
+- `nums` is sorted in non-decreasing order.
+
+## Solution
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+var sortedSquares = function(nums) {
+  let n = nums.length;
+  let ans = new Array(nums.length);
+  let left = 0, right = nums.length - 1;
+
+  for (let i = n -1; i >= 0; i--){
+    let square;
+    if(Math.abs(nums[left]) < Math.abs(nums[right])){
+      square = nums[right];
+      right--;
+    }else{
+      square = nums[left];
+      left++;
+    }
+    ans[i] = square*square;
+  }
+  return ans;
+};
+```

docs/solutions/(two-pointers)/01-reverse-string.mdx

@@ -1,10 +0,0 @@
----
-title: '344. Reverse String'
-sidebar:
-  badge: 'Easy'
----
-
-<Badge variant="accent">Two Pointers</Badge>
-<Badge>[Source](https://leetcode.com/problems/reverse-string/)</Badge>
-
-## Description

docs/solutions/(two-pointers)/02-squares-of-a-sorted-array.mdx

@@ -1,5 +0,0 @@
----
-sidebar:
-  icon: code
-  badge: '977'
----