CODEWITHSUNDEEP
c++dictionary
tkrishtop
tkrishtop

Reputation: 816

How to fulfill a map by max values with a help of triplet operator

I have a map, which I want to fulfill by max values. What I want: 1. if key doesn't exist or value > mymap[key] then mymap[key] = value 2. otherwise, I don't want to rewrite mymap[key] value

I have strong impression that everything written below could be done in one line with the help of triplet operator

    if (mymap.find(key) != mymap.end()) 
    {
        mymap[key] = value;
    }
    else
    {
        if (value > mymap[key]) mymap[key] = value;
    }

I'd do smth like

mymap[key] = value > mymap[key] ? value : mymap[key];

but if key doesn't exists this would create mymap[key] = 0, and the problem is that value could be negative.

Any ideas? Thanks a lot for your help in advance!

Upvotes: 0

Views: 48

Answers (1)

RyanP
RyanP

Reputation: 1918

As mentioned in the comments, you search the map for a key several times. Generally it is best to save the result of find in order to use it for manipulations later so you aren't researching the map for the key each time.

How about this?

const auto it = mymap.find(key);
if (it != mymap.end())
{
    it->second = std::max(value, it->second);
}
else
{
    mymap.emplace(key, value);
}

Upvotes: 1

Related Questions