Backend Developer

Given an integer array nums, return all unique triplets [nums[i], nums[j], nums[k]] such that:

1. i, j, and k are distinct indices (i != j, i != k, j != k).
2. The sum of the triplet equals zero: nums[i] + nums[j] + nums[k] == 0.

Input:

• nums: Array of integers

Output:

• A list of all unique triplets satisfying the conditions.

Constraints:

• Each triplet must consist of unique indices.
• The solution should avoid returning duplicate triplets.

Given an m x n integer matrix, if an element is 0, set its entire row and column to 0.

Input:

• matrix: 2D array of integers with dimensions m x n

Output:

• The modified matrix after setting rows and columns to 0 wherever a zero is present.

Constraints:

• Perform the operation in-place if possible.

You are given an n x n integer matrix board labeled from 1 to n² in a Boustrophedon style, starting from the bottom-left (board[n-1][0]) and alternating direction each row. You start on square 1.

Rules of the Game:

1. In each move, roll a standard six-sided die to choose a destination square next in the range [curr + 1, min(curr + 6, n²)].
2. If next has a snake or ladder (board[r][c] != -1), move to its destination.
3. You only follow one snake or ladder per dice roll. If the destination leads to another snake or ladder, do not follow it.
4. The game ends when you reach square n².

Task:

• Return the minimum number of dice rolls required to reach square n². Return -1 if it is impossible.

Input:

• board: n x n integer matrix with -1 for normal squares and a positive integer for snake/ladder destinations

Output:

• Integer representing the least number of dice rolls to reach the end, or -1 if unreachable

Constraints:

• Squares 1 and n² are never the start of a snake or ladder.

What is database normalization in DBMS? Describe the various normal forms with examples, and explain why normalization is important.