Implement array rotations and CSV keyword search

Problem A — Rotate an array left/right by k

You are given an integer array nums of length n and an integer k.

1. Implement rotateLeft(nums, k) that returns the array after rotating it left by k positions.
2. Implement rotateRight(nums, k) that returns the array after rotating it right by k positions.

Notes / Constraints

• k can be larger than n; treat k as k % n.
• Handle edge cases like n = 0 or n = 1.
• Clarify in your solution whether you modify in-place or return a new array.

Example

• nums = [1,2,3,4,5], k = 2
  • left rotate → [3,4,5,1,2]
  • right rotate → [4,5,1,2,3]

---

Problem B — Find keyword occurrences in a CSV text

You are given a CSV document as a single string csvText.

• Rows are separated by newline characters \n.
• Columns are separated by commas ,.
• Assume fields do not contain escaped commas or quoted strings (i.e., simple CSV).

Task

Given csvText and a keyword key, return all occurrences of key in the document.

For each occurrence, return:

• row: the 0-based row number
• col: the 0-based column number
• pos: the 0-based character index within that cell where the match begins

Return results in row-major order.

Variant

Extend the function to accept multiple keywords keys[] and return occurrences for any of them (you may also include which keyword matched).

Example

csvText = "foo,bar\nxxfood,barfoo", key = "foo"

• Row 0, Col 0, Pos 0 ("foo")
• Row 1, Col 0, Pos 2 ("xxfood")
• Row 1, Col 1, Pos 3 ("barfoo")

(Exact output format is up to you; it just needs to include row/col/pos.)

Rotate an Array Left or Right by k

You are given an integer array nums of length n, an integer k, and a string direction that is either "left" or "right". Return a NEW array that is nums rotated by k positions in the given direction.

Rules:

• k may be larger than n; treat it as k % n.
• Handle edge cases: n = 0 returns an empty array, n = 1 returns the array unchanged.
• A left rotation by k moves the first k elements to the end; a right rotation by k moves the last k elements to the front.

Example: nums = [1,2,3,4,5], k = 2

• direction "left" -> [3,4,5,1,2]
• direction "right" -> [4,5,1,2,3]

Constraints

• 0 <= n <= 10^5
• 0 <= k <= 10^9
• direction is either "left" or "right"
• -10^9 <= nums[i] <= 10^9

Hints

1. Reduce k modulo n first so that rotations larger than the array length wrap correctly.
2. A left rotation by k is a slice split: nums[k:] + nums[:k].
3. A right rotation by k is equivalent to a left rotation by n - k: nums[n-k:] + nums[:n-k].
4. Guard the n == 0 case before computing k % n to avoid a division-by-zero.

Find Keyword Occurrences in Simple CSV

You are given a CSV document as a single string csvText and a keyword key.

• Rows are separated by newline characters \n.
• Columns are separated by commas ,.
• Fields are simple: no quoted strings and no escaped commas.

Return every occurrence of key as a triple [row, col, pos], where:

• row is the 0-based row index,
• col is the 0-based column index within that row,
• pos is the 0-based character index inside that cell where the match begins.

Matches may overlap (e.g. key = "aa" in "aaa" matches at positions 0 and 1). Return results in row-major order (rows in order, then columns in order, then by position within a cell). If key is empty, return an empty list.

Example: csvText = "foo,bar\nxxfood,barfoo", key = "foo" -> [[0,0,0], [1,0,2], [1,1,3]]

Constraints

• 0 <= len(csvText) <= 10^5
• 0 <= len(key) <= 10^3
• csvText uses '\n' as the row separator and ',' as the column separator
• Fields contain no quoted strings or escaped commas
• Matches may overlap

Hints

1. Split csvText on '\n' to get rows, then split each row on ',' to get cells; the indices of these splits are your row and col.
2. Within a cell, repeatedly call find(key, start) and advance start to idx + 1 (not idx + len(key)) so overlapping matches are counted.
3. Stop the inner loop when find returns -1.
4. Treat an empty key as a special case and return no matches to avoid an infinite loop.