thrust

◆ merge() [4/4]

template<typename InputIterator1 , typename InputIterator2 , typename OutputIterator , typename StrictWeakCompare >
OutputIterator thrust::merge ( InputIterator1  first1,
InputIterator1  last1,
InputIterator2  first2,
InputIterator2  last2,
OutputIterator  result,
StrictWeakCompare  comp 
)

merge combines two sorted ranges [first1, last1) and [first2, last2) into a single sorted range. That is, it copies from [first1, last1) and [first2, last2) into [result, result + (last1 - first1) + (last2 - first2)) such that the resulting range is in ascending order. merge is stable, meaning both that the relative order of elements within each input range is preserved, and that for equivalent elements in both input ranges the element from the first range precedes the element from the second. The return value is result + (last1 - first1) + (last2 - first2).

This version of merge compares elements using a function object comp.

Parameters
first1The beginning of the first input range.
last1The end of the first input range.
first2The beginning of the second input range.
last2The end of the second input range.
resultThe beginning of the merged output.
compComparison operator.
Returns
The end of the output range.
Template Parameters
InputIterator1is a model of Input Iterator, InputIterator1's value_type is convertable to StrictWeakCompare's first_argument_type. and InputIterator1's value_type is convertable to a type in OutputIterator's set of value_types.
InputIterator2is a model of Input Iterator, InputIterator2's value_type is convertable to StrictWeakCompare's second_argument_type. and InputIterator2's value_type is convertable to a type in OutputIterator's set of value_types.
OutputIteratoris a model of Output Iterator.
StrictWeakCompareis a model of Strict Weak Ordering.
Precondition
The ranges [first1, last1) and [first2, last2) shall be sorted with respect to comp.
The resulting range shall not overlap with either input range.

The following code snippet demonstrates how to use merge to compute the merger of two sets of integers sorted in descending order.

#include <thrust/merge.h>
...
int A1[6] = {11, 9, 7, 5, 3, 1};
int A2[7] = {13, 8, 5, 3, 2, 1, 1};
int result[13];
int *result_end = thrust::merge(A1, A1 + 6, A2, A2 + 7, result, thrust::greater<int>());
// result = {13, 11, 9, 8, 7, 5, 5, 3, 3, 2, 1, 1, 1}
See also
http://www.sgi.com/tech/stl/merge.html
sort
is_sorted