The Standard Library only provides basic and common containers and algorithms. It is impossible for them to include everything.
A vector is an alternative to built-in arrays that supports random accessing and reallocating, a list is much like a link list, and a map, using the Binary-Tree structure, acts just like a dictionary.
I suggest that an ACM competetor not use the Standard Libarary unless the performance is not too important. We have found that programs using STL is on average 20% slower than those which use your own code even when compiled under Release Mode.