HackerRank Capitalize! problem solution in Python

In this HackerRank Capitalize problem solution in python, You are asked to ensure that the first and last names of people begin with a capital letter in their passports. 

Given a full name, your task is to capitalize the name appropriately.

Problem solution in Python 2 programming.

# Enter your code here. Read input from STDIN. Print output to STDOUT
import string

words = raw_input().split(' ')
for i in xrange(len(words)):
    words[i] = string.capitalize(words[i])

print ' '.join(words)

Problem solution in Python 3 programming.

# Complete the solve function below.
def solve(s):
    for x in s[:].split():
        s = s.replace(x, x.capitalize())
    return s

Problem solution in pypy programming.

def capitalize(string):
    os=""
    for idx,x in enumerate(string):
        #print (x,idx,str1[idx-1])
        os+=x.upper() if string[idx-1]==" " or idx == 0 else x
    return "".join(os)

Problem solution in pypy3 programming.

def capitalize(string):
    s=""
    space=True
    for x in string :
        if space and x!=' ':
            s=s+x.upper() 
            space=False
        elif x==' ':
            s=s+x
            space=True
        else :
            s=s+x
                    
    return s