Two words are anagrams of one another if their letters can be rearranged to form the other word. Given a string, split it into two contiguous substrings of equal length. Determine the minimum number of characters to change to make the two substrings into anagrams of one another.

anagram.rb

#
# Complete the 'anagram' function below.
#
# The function is expected to return an INTEGER.
# The function accepts STRING s as parameter.
#

def anagram(s)
    n = s.length
        return -1 if n % 2 == 1
    n /= 2
    a = s[0, n].split('').sort
    b = s[n, s.length/2].split('').sort
    if a == b
        return 0
    end
    hash_a = Hash.new(0)
    hash_b = Hash.new(0)
    a.each{|i| hash_a[i] += 1}
    b.each{|j| hash_b[j] += 1}
    keys = hash_a.keys & hash_b.keys
    
    a1 = hash_a.select{ |k, v| keys.include? k }
    b1 = hash_b.select{ |k, v| keys.include? k }
    # num1 = a1.values.sum
    # num2 = b1.values.sum
    # print a, b, hash_a, hash_b , keys , a1, b1,num1, num2, "\n"
    total = 0
    for i in keys 
        total += [hash_a[i], hash_b[i]].min        
    end
    return n - total
end