Can not compile merge sort tree structure? - c++

Question

I was trying to implement merge sort tree structure but whenever i
try to merge child vector to parent vector i get compilation error . I
am stuck here .
class merge_sort_tree {
vector<int>input;
vector<vector<int> >tr;
int n;
public:
merge_tree(vector<int >p) {
n = p.size();
input = p;
tr.resize(5 * n);
}
void build(int root, int l, int r) {
if (l == r)
{
tr[root] = {input[l]};
}
int m = l + (r - l) / 2;
build(2 * root, l, m);
build(2 * root + 1, m + 1, r);
//temporary vector for merging child vectors
vector<int>tmp(tr[2 * root].size() + tr[2 * root + 1].size());
// merging child vector and storing result in tmp
merge(tr[2 * root].begin(), tr[2 * root].end(),
tr[2 * root + 1].begin(), tr[2 * root + 1].end(),
tmp.begin(), tmp.end() );
tr[root]=tmp;
}
};
In file included from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\stl_algobase.h:71:0,
from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\char_traits.h:39,
from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\ios:40,
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\mingw32\bits\stdc++.h:52,
from C:\Users\Ayuu\Desktop\codes\test3.cc:1:
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\predefined_ops.h: In instantiation of 'constexpr bool __gnu_cxx::__ops::_Iter_comp_iter<_Compare>::operator()(_Iterator1, _Iterator2) [with _Iterator1 = __gnu_cxx::__normal_iterator >; _Iterator2 = __gnu_cxx::__normal_iterator >; _Compare = __gnu_cxx::__normal_iterator >]':
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\stl_algo.h:4751:14: required from '_OutputIterator std::__merge(_InputIterator1, _InputIterator1, _InputIterator2, _InputIterator2, _OutputIterator, _Compare) [with _InputIterator1 = __gnu_cxx::__normal_iterator >; _InputIterator2 = __gnu_cxx::__normal_iterator >; _OutputIterator = __gnu_cxx::__normal_iterator >; _Compare = __gnu_cxx::__ops::_Iter_comp_iter<__gnu_cxx::__normal_iterator > >]'
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\stl_algo.h:4858:37: required from '_OIter std::merge(_IIter1, _IIter1, _IIter2, _IIter2, _OIter, _Compare) [with _IIter1 = __gnu_cxx::__normal_iterator >; _IIter2 = __gnu_cxx::__normal_iterator >; _OIter = __gnu_cxx::__normal_iterator >; _Compare = __gnu_cxx::__normal_iterator >]'
C:\Users\Ayuu\Desktop\codes\test3.cc:43:38: required from here
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\predefined_ops.h:123:18: error: no match for call to '(__gnu_cxx::__normal_iterator >) (int&, int&)'
{ return bool(_M_comp(*__it1, *__it2)); }

Answer 1

Look at this line, it expected one iterator, you gave 2
error: no match for call to '(__gnu_cxx::__normal_iterator >) (int&, int&)' { return bool(_M_comp(*__it1, *__it2)); }
Remove tmp.end() from your merge function. It requires 5 arguments not 6.
merge(tr[2 * root].begin(), tr[2 * root].end(),
tr[2 * root + 1].begin(), tr[2 * root + 1].end(),
tmp.begin());
This should work.