I am trying to add the elements from a map to a pair vector, and then sort the vector according to the value, but i dont want to add elements that have the same value, and i can't figure out how to make such an if statement.

The map contains the amount of times a word was repeated in the input in main() and the word itself, and i want to sort the vector that has the map elements, but i dont want to repeat words that have been repeated the same amount of times.

This is what i have so far:

bool compara(pair<string, unsigned int>& a,
    pair<string, unsigned int>& b)
{
    return a.second > b.second;
}

void sortP(map<string, unsigned int> &M, unsigned int x)
{
    vector<pair<string, unsigned int> > A;

    for (auto& it : M) {  
        if(find(A.begin(), A.end(), it.second) == A.end())    // this is the part that 
               A.push_back(it);                               //       doesn't work  
    }

    sort(A.begin(), A.end(), compara);

    for (auto& it : A) {

        cout << it.second << "\t"
            << it.first << endl;
    }
    cout << endl << endl;
    // this is where i want to output the element of the vector that appears on the 'x' 
    // position, after it was sorted
}

I apologize if the terminology isn't exactly correct, i have just started getting accustomed to working with maps and pairs.

CodePudding user response：

Since you are searching through a vector of pairs, you need to use std::find_if() instead of std::find() to find a vector element that matches a particular field of the pair, eg:

for (auto& it : M) {  
    if (find_if(A.begin(), A.end(), [&](pair<string, unsigned int>& p){ return p.second == it.second; }) == A.end())
        A.push_back(it);
}

Alternatively, you could just use another map instead of a vector, using it.second as the key type, and letting the map handle the sorting and duplicate handling for you.