36 lines
1.1 KiB
Julia
Executable File
36 lines
1.1 KiB
Julia
Executable File
# This type allows to compute length once and for all
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struct StringWithLength{T <: AbstractString} <: AbstractString
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s::T
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l::Int
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end
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string_with_length(s::AbstractString) = StringWithLength(s, length(s))
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Base.length(s::StringWithLength) = s.l
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Base.iterate(s::StringWithLength, i::Integer = firstindex(s.s)) = iterate(s.s, i)
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Base.nextind(s::StringWithLength, i::Int, n::Int = 1) = nextind(s.s, i, n)
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Base.ncodeunits(s::StringWithLength) = ncodeunits(s.s)
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Base.isvalid(s::StringWithLength, i::Int) = isvalid(s.s, i)
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function reorder(s1::AbstractString, s2::AbstractString)
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s1 = string_with_length(s1)
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s2 = string_with_length(s2)
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if length(s1) <= length(s2)
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return s1, s2
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else
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return s2, s1
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end
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end
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function common_prefix(s1::AbstractString, s2::AbstractString)
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x1 = iterate(s1)
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x2 = iterate(s2)
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l = 0
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while (x1 !== nothing) & (x2 !== nothing)
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ch1, state1 = x1
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ch2, state2 = x2
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ch1 != ch2 && break
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l += 1
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x1 = iterate(s1, state1)
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x2 = iterate(s2, state2)
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end
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return l, x1, x2
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end |