data-structures/

Spiral Matrix

Answer

class SpiralMatrix
    def self.gen(dim)
        mat = Array.new(dim) { Array.new(dim)}

        count = 1
        startRow = 0
        startCol = 0
        endRow = dim - 1
        endCol = dim - 1

        while startRow <= endRow && startCol <= endCol
            # top row
            i = startCol
            while i <= endCol do
                mat[startRow][i] = count
                count += 1
                i += 1
            end
            startRow += 1

            # far col
            i = startRow
            while i <= endRow do
                mat[i][endCol] = count
                count += 1
                i += 1
            end
            endCol -= 1

            # bottow row
            i = endCol
            while i >= startCol do
                mat[endRow][i] = count
                count += 1
                i -= 1
            end
            endRow -= 1

            # closest col
            i = endRow
            while i >= startRow do
                mat[i][startCol] = count
                count += 1
                i -= 1
            end
            startCol += 1
        end

        return mat
    end
end
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