Q:

String parsing and find common white space location

I am trying to parse a string and find a common white space location. 
Here is my strings 
abc   xyz 123   456
cba 1234a 45623 say
avc  4567 bv    456

There can any number of strings.  I need a generic alogorithm preferable in c# where I can find out the common white space locations in above strings. 
For example, in above strings common locations are
4, 10 ,16 

which has white space in every string. 
Approaches I have been trying includes Intersect , and to get all possible spaces and then compare to find out the common ones but I am trying to find out the optimal solution. 

A:

var stringList = new[] { "abc   xyz 123   456", "cba 1234a 45623 say", "avc  4567 bv    456" };
var shortest = stringList. OrderBy(s => s.Length).First();
var result = new Collection<int>();

for (int i = 0; i < shortest. Length; i++)
{
    if (stringList. All(c => c[i] == ' ')) result. Add(i+1);
}

// Test the results
foreach (var index in result)
{
    Console. WriteLine(index);
}

