36 lines
774 B
Lua
36 lines
774 B
Lua
N = 8
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-- We'll use nil to indicate no queen is present.
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grid = {}
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for i = 0, N do
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grid[i] = {}
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end
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function can_find_solution(x0, y0)
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local x0, y0 = x0 or 0, y0 or 1 -- Set default vals (0, 1).
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for x = 1, x0 - 1 do
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if grid[x][y0] or grid[x][y0 - x0 + x] or grid[x][y0 + x0 - x] then
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return false
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end
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end
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grid[x0][y0] = true
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if x0 == N then return true end
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for y0 = 1, N do
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if can_find_solution(x0 + 1, y0) then return true end
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end
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grid[x0][y0] = nil
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return false
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end
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if can_find_solution() then
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for y = 1, N do
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for x = 1, N do
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-- Print "|Q" if grid[x][y] is true; "|_" otherwise.
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io.write(grid[x][y] and "|Q" or "|_")
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end
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print("|")
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end
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else
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print(string.format("No solution for %d queens.\n", N))
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end
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