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stable_partition
Same as partition(), but preserves the relative order of matching and nonmatching elements
Key Facts
Gyroscopic Couple: The rate of change of angular momentum (= Moment of Inertia.
= Angular velocity
= Angular velocity of precession.
Blaise Pascal (1623-1662) was a French mathematician, physicist, inventor, writer and Catholic philosopher.
Leonhard Euler (1707-1783) was a pioneering Swiss mathematician and physicist.
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 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 exactlylast - 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.Example:
Example - stable_partition algorithm
Problem
This program illustrates the functionality of stable_partition() algorithm.
Workings
#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; }
Solution
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
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
References