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44 lines
1.0 KiB
Ruby
44 lines
1.0 KiB
Ruby
# Traverse 2D Array in a spiral
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# Set 4 variables to define the outer bounds
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# of the matrix - left, right, top, bottom
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# Set a direction: 0 -> left to right, 1 -> top to bottom,
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# 2 -> right to left, 3 -> bottom to top
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# At each iteration check which direction is set and
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# iterate through those values in the matrix
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# Then increment the outer bound by 1 to show
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# that that area has already been traced
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def traverse_spiral(matrix)
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l = 0
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r = matrix[0].length - 1
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b = matrix.length - 1
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t = 0
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dir = 0
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# loop until top bound equals bottom bounds and left bounds equals right
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while t <= b && l <= r
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if dir == 0
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(l..r).each { |left_index| puts matrix[t][left_index] }
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t += 1
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end
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if dir == 1
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(t..b).each { |top_col_ind| puts matrix[top_col_ind][r] }
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r -= 1
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end
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if dir == 2
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r.downto(l) { |right_index| puts matrix[b][right_index] }
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b -= 1
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end
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if dir == 3
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b.downto(t) { |bot_col_index| puts matrix[bot_col_index][l] }
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l += 1
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end
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dir = (dir + 1) % 4
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end
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end
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