main.rb

# divide and conquer

# @param {String[]} strs
# @return {String}
deflongest_common_prefix(strs)
ifstrs.nil? || strs.size <= 0
return""
end

longest_common_prefix_helperstrs,0,strs.size - 1
end

deflongest_common_prefix_helper(strs,left,right)
ifleft == right
strs[left]
else
mid=(left + right) / 2
str1=longest_common_prefix_helperstrs,left,mid
str2=longest_common_prefix_helperstrs,mid + 1,right
common_prefixstr1,str2
end
end

defcommon_prefix(str1,str2)
minimum=[str1.size,str2.size].min
result=""

0.upto(minimum)do |i|
ifstr1[i] != str2[i]
result=str1[0...i]
returnresult
end
end

result=str1[0...minimum]
result
end