Learn and practice the Sliding Window, and Union Find patterns to solve coding interview problems.

Speedrun the Microsoft Coding Interview: Top Problems in Python

Each pattern in this module exemplifies the power of dissecting a problem in detail and figuring out the least expensive operations required to solve it. In the Sliding Window pattern, we’ll gain practice in various techniques to ensure that a solution that seems to require nested loops actually executes in linear time. Using the Union Find pattern, we’ll learn to solve a diverse set of problems using the disjoint-set data structure.

Elegant by Design

# Statement

Let’s consider a scenario with an $(m \times n)$ 2D grid containing binary numbers, where `'0'` represents water and `'1'` represents land. If any `'1'` cells are connected to each other horizontally or vertically (not diagonally), they form an island. Your task is to return the total number of islands in the grid.

**Constraints:**

* $1 \leq$ `grid.length` $\leq 50$

* $1 \leq$ `grid[i].length` $\leq 50$

* `grid[i][j]` is either `'0'` or `'1'`.

# Examples

Try to solve the Number of Islands problem.

Sliding Window

Union Find

Conclusion

Number of Islands

Statement