find the maximum value in a hash table and then printing all the variables with that value (in C)

Question

Having a struct like this:

typedef struct person {
    char *name;
    int age;
} person

I insert each person I create in a hash table and what I want to do is find the oldest people, like this:

Oldest People:
Austin 29
John 29
Matthew 29

I was wondering if there was a more efficent way to find the maximum age than searching the hash table twice: one to find the maximum value and the other to print all the people with the max value.

Answer 1

You can determine the maximum age while inserting. You need that if-clause anyways, but this way you save walking over the hash table for that.

Apart from that, you didn't say what is the key of your hash table. I assume, it is the name, since you didn't mention resolving age collisions and you mentioned the need for a second pass.

And I guess the purpose of your hash table is not just solving this problem. But if it was, I wouldn't use a hash table but just keep a list of the names with the current maximum age and reset it as soon as the maximum age changes. The list could be implemented as an array + size variable in case you know the maximum size, otherwise eg with a linked list of fixed size blocks.