ArrayHopper You are given an array of integers with values greater than or equal to 0, for example: [5, 6, 0, 4, 2, 4, 1, 0, 0, 4] You will develop and implement an algorithm to traverse the array in the shortest number of “hops” starting at index 0, Start at the first (0th) index of the array, look at the array value there, and you can hop forw…

minHops.py

import fileinput

def find_min(a, x, length):
	if length == 0: return float('inf'), -1
	if len(a) == (x+1): return 1, 'out'
	h = reduce(lambda x, y: (a[y], y) if x[0] > a[y] else x, range(x+1, min(len(a), x+1+length)), (float('inf'), -1))
	return h[0]+1, h[1]

def find_min_hops(a):
	length = len(a)
	hops = [float('inf') for x in range(length)]
	index = [-1 for x in range(length)]

	for x in range(length-1, -1, -1):
		hops[x], index[x] = find_min(hops, x, a[x]) 
		# print hops[x], index[x]

	curr_index = 0
	if index[curr_index] == -1: 
		print 'failure'
		return
	print '0,', 
	while(index[curr_index] != 'out'):
		print str(index[curr_index])+',',
		curr_index = index[curr_index]
	print 'out'

# a = []
# for line in fileinput.input():
#     a.append(int(line.strip()))
# fileinput.close()

#ERRORS: 
# 1) reverse(range) was throwing up -> reversed(range) not reverse()
# OR range(len(a)-1, -1, -1)
# OR a = range(len(a)); a.reverse(); 
# 2) enumerate always starts from 0...even for enumerate(arr[4:7])
# Instead loop as i in range(4,7) ... use arr[i] inside
# 3) '+' doesnt work b/w int and str ...convert int to str by str()
# float('inf') as inf
# inputfile.input() takes argv[1:] all filenames items to iterate
# raw_input() for input() from user
#Use of reduce, filter, map, and list-comprehension


a = [1, 6, 0, 4, 2, 3, 1, 2, 0, 4]
find_min_hops(a)