Leetcode - Spiral Matrix II

Input: 3
Output:
[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]

Loop  4 directions and fill it.

func generateMatrix(n int) [][]int {
    directions := []string{"right", "down", "left", "up"}
    result := make([][]int, n)
    for i := 0; i < n; i++ {
        result[i] = make([]int, n)
    }
    rowStart := 0
    rowEnd := n
    columnStart := 0
    columnEnd := n
    visited := 1
    for (visited - 1) != (n*n) {
        for _, d := range directions {
            if d == "right" {
                for i := columnStart; i < columnEnd; i++ {
                    result[rowStart][i] = visited
                    visited++
                }
                rowStart++
            }
            if d == "down" {
                for i := rowStart; i < rowEnd; i++ {
                    result[i][columnEnd-1] = visited
                    visited++
                }
                columnEnd--
            }
            if d == "left" {
                for i := columnEnd - 1; i >= columnStart; i--{
                    result[rowEnd - 1][i] = visited
                    visited++
                }
                rowEnd--
            }
            if d == "up" {
                for i := rowEnd - 1; i >= rowStart; i-- {
                    result[i][columnStart] = visited
                    visited++
                }
                columnStart++
            }
            if (rowStart == rowEnd && columnStart == columnEnd) || (visited-1 == n*n) {
                break
            }
        }
        if rowStart == rowEnd && columnStart == columnEnd {
            break
        }
    }
    
    return result
}

# @param {Integer} n
# @return {Integer[][]}
def generate_matrix(n)
    visited = 1
    row_start = 0
    row_end = n - 1
    column_start = 0
    column_end = n - 1
    directions = ["right", "down", "left", "up"]
    grid = Array.new(n){Array.new(n, 0)}

    while visited - 1 != n * n
        directions.each do |d|
            if d == "right"
                for i in column_start..column_end
                    grid[row_start][i] = visited
                    visited += 1
                end
                row_start += 1
            end
            if d == "down"
                for i in row_start..row_end
                    grid[i][column_end] = visited
                    visited += 1
                end
                column_end -= 1
            end
            
            if d == "left"
                i = column_end
                while i >= column_start
                    grid[row_end][i] = visited
                    visited += 1
                    i -= 1
                end
                row_end -= 1
            end
            
            if d == "up"
                i = row_end
                while i >= row_start
                    grid[i][column_start] = visited
                    visited += 1
                    i -= 1
                end
                column_start += 1
            end

            break if  visited - 1 == n*n      
        end
        break if visited - 1 == n*n
        
    end

    return grid
end

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