Arranges list in negatives and positives and creates alternate of those numbers

squdrun.py

a = map(int, raw_input().split())

def rearrange(li):
	val = len(li)-1
	for i in range(len(li)):
		if li[i]>0 and i<mid:
			while True:
				if li[val]<0:
					li[i], li[val] = li[val], li[i]
					break
				val -=1
	return li

def alternate(li):
	count = 0		
	for i in range(1,len(li),2):
		li[i], li[len(li)-i] = li[len(li)-i], li[i]
		count+=1
		if count==mid/2:
			break
	return li

if __name__ == "__main__":

	mid = len(a)/2

	a = rearrange(a)
	print a

	a = alternate(a)
	print a