leetcode/1260: rotate_right

[tony84727]

No description provided.

[gemini-code-assist]

Code Review

This pull request implements the solution for LeetCode 1260, "Shift 2D Grid", in Rust. The feedback suggests adding a guard clause to handle empty grids safely, preventing potential panics from division by zero or unwrapping empty options. Additionally, it recommends using chunks_exact to group the flattened vector into rows, which is a more idiomatic and efficient approach than using nested loops with pre-allocated vectors.

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[gemini-code-assist]

The current implementation has a few areas for improvement:

1. Safety: If grid is empty or contains empty rows, calling .unwrap() on grid.first() or performing modulo division by m * n (which would be 0) will cause a panic. Adding a guard clause makes the function robust.
2. Efficiency & Idiomatic Rust: Instead of pre-allocating shifted with zeros and manually copying elements using nested loops, you can use chunks_exact to group the flat vector into rows and collect them directly. This avoids double-initialization and is much more idiomatic.

        if grid.is_empty() || grid[0].is_empty() {
            return grid;
        }
        let m = grid[0].len();
        let mut elements: Vec<i32> = grid.into_iter().flatten().collect();
        elements.rotate_right(k as usize % elements.len());
        elements.chunks_exact(m).map(|chunk| chunk.to_vec()).collect()