Merge Sort in ruby.

# Merge Sort in ruby.

def merge_sort(array)
n = array.length
if n > 1
mid = n/2
lefthalf = array[0..mid-1]
righthalf = array[mid..n-1]
merge_sort lefthalf
merge_sort righthalf
i = j = k = 0
while i < lefthalf.length and j < righthalf.length
if lefthalf[i] < righthalf[j]
array[k] = lefthalf[i]
i = i+1
else
array[k] = righthalf[j]
j = j+1
end
k += 1
end

while i < lefthalf.length
array[k] = lefthalf[i]
i = i+1
k = k+1
end

while j < righthalf.length
array[k] = righthalf[j]
j = j+1
k = k+1
end
end
end

print array = [6,5,3,1,8,7,2,4]
merge_sort array
print array

Selection Sort in ruby.

# Selection Sort in ruby.

def selection_sort(array)
n = array.length-1
for i in 0..n-1
min = i
j = i + 1
for j in j..n
if array[min] > array[j]
min = j
end
end
if i != min
array[i],array[min] = array[min],array[i]
end
end
end

array = [6,5,3,1,8,7,2,4]
selection_sort array
print array

Bubble sort in ruby.

# Bubble Sort in ruby.

def bubble_sort(array)
for i in 0..array.length - 1
for j in 0..array.length - 2
if array[j] > array[j+1]
array[j],array[j+1] = array[j+1],array[j]
end
end
end
end

array = [6,5,3,1,8,7,2,4]
bubble_sort array
print array

Insertion Sort in ruby.

# Insertion Sort in ruby.

def insertion_sort(array)
for i in 1..array.length - 1
j = i
temp = array[i]
while ((j>0) and (array[j-1] > temp))
array[j] = array[j-1]
j -= 1
end
array[j] = temp
end
return array
end

array = [6,5,3,1,8,7,2,4]
insertion_sort array
print array