Reorder vector using a vector of indices

Question

I\'d like to reorder the items in a vector, using another vector to specify the order:

char   A[]     = { \'a\', \'b\', \'c\' };
size_t ORDER[] = { 1, 0, 2 }         


        

Answer 1

Your code is broken. You cannot assign to vA and you need to use template parameters.

vector REORDER(const vector& vA, const vector& vOrder)  
{   
    assert(vA.size() == vOrder.size());  
    vector vCopy(vA.size()); 
    for(int i = 0; i < vOrder.size(); ++i)  
        vCopy[i] = vA[ vOrder[i] ];  
    return vA;
} 

The above is slightly more efficient.