"in instantiation of function template specialization 'std::max<int, int>' requ-CodePudding

While trying to solve http://www.usaco.org/index.php?page=viewproblem2&cpid=891, I coded :

vector<int> abc(3) ;
vector<int> counter(3) ;
for (int i=0; i<3; i  ) {
    abc[i] = i ;
}

for (int i=0; i<3; i  ) {
    int a,b,g ;
    ifstr >> a >> b >> g ;
    a-- ;
    b-- ;
    g-- ;

    swap(abc[a], abc[b]) ;
    counter[abc[g]]   ;
}
ofstr << std::max(counter[0], counter[1], counter[2]) ;
return 0 ;

I got 4 overloads on my max() function. How do I solve this problem?

CodePudding user response：

The correct way to use std::max with anything else than 2 arguments is by using an initializer list:

ofstr << std::max( { counter[0], counter[1], counter[2] } );
//                 ^                                    ^

Alternatively, you could use std::max_element which doesn't require a copy of all the elements like the initializer list does. Instead you give it the begin and end iterators of your container:

ofstr << *std::max_element(std::begin(counter), std::end(counter));
//       ^

Note that it returns an iterator to the found element (or the end iterator) and it needs to be dereferenced to get the actual value, hence the * above.

CodePudding user response：

Given you counter, you can do this

ofstr << *std::max_element(counter.begin(), counter.end());

(if you include the alogirhtm header).