| 44 |  | * <p> Preconditions: </p> | 
| 45 |  | * | 
| 46 |  | */ | 
| 47 | < | template<class BidirectionalIterator, template<typename ELEM, typename = std::allocator<ELEM> > class IteratorContainer> | 
| 48 | < | bool next_combination(IteratorContainer<BidirectionalIterator>& iterContainer, BidirectionalIterator first, BidirectionalIterator last) { | 
| 47 | > | template<class RandomAccessIterator, template<typename ELEM, typename = std::allocator<ELEM> > class IteratorContainer> | 
| 48 | > | bool next_combination(IteratorContainer<RandomAccessIterator>& iterContainer, RandomAccessIterator first, RandomAccessIterator last) { | 
| 49 |  | if (first == last) { | 
| 50 |  | return false; | 
| 51 |  | } | 
| 52 |  |  | 
| 53 | < | BidirectionalIterator endIter = --last; | 
| 54 | < | typename IteratorContainer<BidirectionalIterator>::iterator i = iterContainer.end(); | 
| 53 | > | RandomAccessIterator endIter = --last; | 
| 54 | > | typename IteratorContainer<RandomAccessIterator>::iterator i = iterContainer.end(); | 
| 55 |  |  | 
| 56 |  | if (iterContainer.empty()) { | 
| 57 |  | //if sequence is empty, we insert the first iterator | 
| 71 |  | //If j is less than zero, it means it already reaches the last combination of current size. | 
| 72 |  | //For instance, sequence may contain 6, 7, 8, 9 at this time, we need to increase the size | 
| 73 |  | // of combination to 5 | 
| 74 | < | typename IteratorContainer<BidirectionalIterator>::iterator j = i; | 
| 74 | > | typename IteratorContainer<RandomAccessIterator>::iterator j = i; | 
| 75 |  | j--; | 
| 76 |  | while( j >= iterContainer.begin() && *i == *j + 1){ | 
| 77 |  | i--; | 
| 78 |  | j--; | 
| 79 |  | }; | 
| 80 |  |  | 
| 81 | < | BidirectionalIterator biDirIter; | 
| 81 | > | RandomAccessIterator raIter; | 
| 82 |  | if (j - iterContainer.begin() < 0) { //reaches the last combination of current size | 
| 83 |  | //half open range | 
| 84 |  | if (last  - first + 1  == iterContainer.size()) { | 
| 88 |  |  | 
| 89 |  | //push the first currentSize+1 element into sequence | 
| 90 |  |  | 
| 91 | < | for(i = iterContainer.begin(), biDirIter= first; i  != iterContainer.end(); ++i, ++biDirIter) { | 
| 92 | < | *i = biDirIter; | 
| 91 | > | for(i = iterContainer.begin(), raIter= first; i  != iterContainer.end(); ++i, ++raIter) { | 
| 92 | > | *i = raIter; | 
| 93 |  | } | 
| 94 | < | iterContainer.insert(iterContainer.end(), biDirIter); | 
| 94 | > | iterContainer.insert(iterContainer.end(), raIter); | 
| 95 |  |  | 
| 96 |  | return true; | 
| 97 |  | } | 
| 98 |  |  | 
| 99 |  | } else { | 
| 100 |  | ++(*j); | 
| 101 | < | biDirIter = *j; | 
| 101 | > | raIter = *j; | 
| 102 |  | for(; i != iterContainer.end(); ++i) { | 
| 103 | < | ++biDirIter; | 
| 104 | < | *i = biDirIter; | 
| 103 | > | ++raIter; | 
| 104 | > | *i = raIter; | 
| 105 |  | } | 
| 106 |  | return true; | 
| 107 |  | } |