Julia samples (#108)

* Add julialang binary search sample

* Add unit test

* Add julialang selection sort sample

* Change julia suffix to jl

* Add recursion and quick sort with tests

* add quick sort

* Add hash table samples

* Add BFS

* Changed file names

* Add dijkstras

* Add Dijkstras test

04_quicksort/julia/01_loop_sum.jl

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+using Test
+
+function sum(arr)
+    total = 0
+    for x in arr
+        total += x
+    end
+    return total
+end
+
+@test sum([1,2,3,4]) == 10

04_quicksort/julia/02_recursive_sum.jl

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+using Test
+
+function sum(arr)
+    if isempty(arr)
+        return 0
+    end
+    return arr[1] + sum(arr[2:end])
+end
+
+@test sum([1,2,3,4]) == 10

04_quicksort/julia/03_recursive_cout.jl

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+using Test
+
+function count(arr)
+    if isempty(arr)
+        return 0
+    end
+    return 1 + count(arr[2:end])
+end
+
+@test count([1,2,3,4]) == 4

04_quicksort/julia/04_recursive_max.jl

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+using Test
+
+function max_(arr)
+    if length(arr) == 1
+        return arr[1]
+    end
+    sub_max = max_(arr[2:end])
+    return arr[1] > sub_max ? arr[1] : sub_max
+end
+
+@test max_([1,5,8,20,9,10]) == 20

04_quicksort/julia/05_quick_sort.jl

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+using Test
+
+function quick_sort(arr)
+    if length(arr) < 2 return arr end
+    pivot = arr[1]
+    less = [i for i in arr[2:end] if i <= pivot]
+    greater = [i for i in arr[2:end] if i > pivot]
+    return vcat(quick_sort(less), [pivot], quick_sort(greater))
+end
+
+@test quick_sort([3,5,2,1,4]) == [1,2,3,4,5]