Question

I have a jagged Array String[][]. Now I need to find the array with a particular value in String[n][0]
what i have a the moment is a simple

foreach foo in bar{
 if(foo[0]==needle){
  return foo;
 }
}

As you may see this is very slow for obvious reasons. I’m new to C# and just saw the indexOf, but how can i use indexOf in a jagged array?

Another way i tought of is Sorting the Array by String[n][0], going to the record in the middle, check if my value is larger or bigger, jump in the half of the upper/lower area and so on, maybe 3 or 4 times so i can find the record faster.

So whats the fastest way of getting the Array in a jagged Array where I only know [][0]?

Answer 1

I would use a Dictionary<int, int[]> where the key is the first item of the array. Dictionaries have constant time access, and are very fast for random access if the entire data fits in memory.