inplace_merge(3C++) - inplace_merge(3C++)
Standard C++ Library Copyright 1998, Rogue Wave Software, Inc.
NAMEinplace_merge
- Merges two sorted sequences into one.
SYNOPSIS
#include <algorithm>
template <class BidirectionalIterator>
void inplace_merge(BidirectionalIterator first,
BidirectionalIterator middle,
BidirectionalIterator last);
template <;class BidirectionalIterator, class Compare>
void inplace_merge(BidirectionalIterator first,
BidirectionalIterator middle,
BidirectionalIterator last,
Compare comp);
DESCRIPTION
The inplace_merge algorithm merges two sorted consecutive ranges
[first, middle) and [middle, last), and puts the result of the merge
into the range [first, last). The merge is stable, which means that if
the two ranges contain equivalent elements, the elements from the first
range always precede the elements from the second.
There are two versions of the inplace_merge algorithm. The first ver‐
sion uses the less than operator (operator<) as the default for compar‐
ison, and the second version accepts a third argument that specifies a
comparison operator.
COMPLEXITY
When enough additional memory is available, inplace_merge does at most
(last - first) - 1 comparisons. If no additional memory is available,
an algorithm with O(NlogN) complexity (where N is equal to last-first)
may be used.
EXAMPLE
//
// merge.cpp
//
#include <algorithm>
#include <vector>
#include <functional>
#include <iostream>
using namespace std;
int main()
{
int d1[4] = {1,2,3,4};
int d2[8] = {11,13,15,17,12,14,16,18};
// Set up two vectors
vector<int> v1(d1,d1 + 4), v2(d1,d1 + 4);
// Set up four destination vectors
vector<int> v3(d2,d2 + 8),v4(d2,d2 + 8),
v5(d2,d2 + 8),v6(d2,d2 + 8);
// Set up one empty vector
vector<int> v7;
// Merge v1 with v2
merge(v1.begin(),v1.end(),v2.begin(),v2.end(),
v3.begin());
// Now use comparator
merge(v1.begin(),v1.end(),v2.begin(),v2.end(),v4.begin(),
less<int>());
// In place merge v5
vector<int>::iterator mid = v5.begin();
advance(mid,4);
inplace_merge(v5.begin(),mid,v5.end());
// Now use a comparator on v6
mid = v6.begin();
advance(mid,4);
inplace_merge(v6.begin(),mid,v6.end(),less<int>());
// Merge v1 and v2 to empty vector using insert iterator
merge(v1.begin(),v1.end(),v2.begin(),v2.end(),
back_inserter(v7));
// Copy all cout
ostream_iterator<int,char> out(cout," ");
copy(v1.begin(),v1.end(),out);
cout << endl;
copy(v2.begin(),v2.end(),out);
cout << endl;
copy(v3.begin(),v3.end(),out);
cout << endl;
copy(v4.begin(),v4.end(),out);
cout << endl;
copy(v5.begin(),v5.end(),out);
cout << endl;
copy(v6.begin(),v6.end(),out);
cout << endl;
copy(v7.begin(),v7.end(),out);
cout << endl;
// Merge v1 and v2 to cout
merge(v1.begin(),v1.end(),v2.begin(),v2.end(),
ostream_iterator<int,char>(cout," "));
cout << endl;
return 0;
}
Program Output1 2 3 41 2 3 41 1 2 2 3 3 4 41 1 2 2 3 3 4 411 12 13 14 15 16 17 1811 12 13 14 15 16 17 181 1 2 2 3 3 4 41 1 2 2 3 3 4 4WARNINGS
If your compiler does not support default template parameters, then you
always need to supply the Allocator template argument. For instance,
you have to write:
vector<int, allocator,int> >
instead of:
vector<int>
If your compiler does not support namespaces, then you do not need the
using declaration for std.
SEE ALSO
merge
Rogue Wave Software 02 Apr 1998 inplace_merge(3C++)
