stable_partition
Same as partition(), but preserves the relative order of matching and nonmatching elements
Definition
The stable_partition() algorithm is defined in the standard header <algorithm> and in the nonstandard backward-compatibility header <algo.h>.
Interface
#include <algorithm>
template < class BidirectionalIterator, class Predicate >
BidirectionalIterator stable_partition(
BidirectionalIterator first,
BidirectionalIterator last,
Predicate pred
);Parameters:
| Parameter | Description |
| first | A bidirectional iterator addressing the position of the first element in the range to be partitioned |
| last | A bidirectional iterator addressing the position one past the final element in the range to be partitioned |
| pred | User-defined predicate function object that defines the condition to be satisfied if an element is to be classified. A predicate takes single argument and returns true or false |
Description
Stable_partition function does the same thing that http://www.codecogs.com/reference/computing/stl/algorithms/modifying/partition.php"partition" , except that the relative order between elements is kept. Thus, stable partition uses more computation time than partition.
Return Value
Returns a bidirectional iterator addressing the position of the first element in the range to not satisfy the predicate condition.
Complexity
Performs exactly last - first applications of the predicate and at most (last -first)*log(last - first) swaps if there is insufficient memory or linear number of swaps if sufficient memory is available.
References
Example 1
This program illustrates the functionality of stable_partition() algorithm.
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;
bool greaterthan(int value )
{ return value > 5; }
int main()
{
vector <int> vec1, vec2;
vector <int>::iterator Iter1, Iter2, result;
int i,j;
for(i = 0; i <= 10; i++)
vec1.push_back(i);
for(j = 0; j <= 4; j++)
vec1.push_back(3);
random_shuffle(vec1.begin(), vec1.end());
cout <<"Random shuffle vector vec1 data:\n";
for (Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout <<*Iter1<<" ";
cout <<endl;
// partition the range with predicate greater than 5...
result = stable_partition (vec1.begin(), vec1.end(), greaterthan);
cout <<"\nThe partitioned set of elements in vec1 is:\n";
for (Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout <<*Iter1<<" ";
cout <<endl;
cout <<"\nThe first element in vec1 fail to satisfy "
"the predicate greaterthan is:\n "<<*result<<endl;
return 0;
}Output:
Random shuffle vector vec1 data:
3 1 9 2 0 3 7 3 4 3 8 5 3 3 10 6
The partitioned set of elements in vec1 is:
9 7 8 10 6 3 1 2 0 3 3 4 3 5 3 3
The first element in vec1 fail to satisfy the predicate greaterthan is:
3