CODEWITHSUNDEEP
pythonsortingmergesort
calvin11
calvin11

Reputation: 187

Problems with MergeSort in Python-3

I have a problem with MergeSort in Python-3.x. This is that the algorithm does not do the sorting. What's my mistakes? Can you help me?

The code is:

def mergeSort(lista):
	#Precondición: elem comparables
	#Postcondición: lista ordenada
	if len(lista) < 2:
		return lista
	medio = len(lista) // 2
	izq = mergeSort(lista[:medio])
	der = mergeSort(lista[medio:])
	return merge(izq,der)

def merge(lista1,lista2):
	#Precondición: listas ordenadas
	#Postcondición: retorna lista con elem de lista1 y lista2
	i,j = 0,0
	resultado = []
	while i<len(lista1) and j<len(lista2):
		if (lista1[i] < lista2[j]):
			resultado.append(lista1[i])
			i += 1
		else:
			resultado.append(lista2[j])
			j += 1
       
	resultado += lista1[i:]
	resultado += lista2[j:]
	return resultado

L = [6,7,-1,0,5,2,3,8]
mergeSort(L)
print(L)

And the result is: 

[6, 7, -1, 0, 5, 2, 3, 8]
[Finished in 0.2s]

Upvotes: 1

Views: 115

Answers (1)

kgf3JfUtW
kgf3JfUtW

Reputation: 14918

How about print(mergeSort(L)). It gives [-1, 0, 2, 3, 5, 6, 7, 8] for me.

The problem with the following code is that L is not even modified. The return value of mergeSort(L) (presumably) gives you the sorted list.

L = [6,7,-1,0,5,2,3,8]
mergeSort(L)
print(L)

Upvotes: 2

Related Questions