-// modified from stl_algo.h: always do com(*first1,*first2) instead of comp(*first2,*first1)
-template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
-OutputIterator mymerge(InputIterator1 first1, InputIterator1 last1,
- InputIterator2 first2, InputIterator2 last2,
- OutputIterator result, Compare comp) {
- while (first1 != last1 && first2 != last2) {
- if (comp(*first1, *first2)) {
- *result = *first1;
- ++first1;
- }
- else {
- *result = *first2;
- ++first2;
- }
- ++result;
- }
- return copy(first2, last2, copy(first1, last1, result));
-}
-
-// like merge(), but three lists with *last2<*first3
-template <class InputIterator1, class InputIterator2, class InputIterator3,
- class OutputIterator, class Compare>
-OutputIterator mymerge3(InputIterator1 first1, InputIterator1 last1,
- InputIterator2 first2, InputIterator2 last2,
- InputIterator3 first3, InputIterator3 last3,
- OutputIterator result, Compare comp) {
- while (first1 != last1 && first2 != last2) {
- if (comp(*first1, *first2)) {
- *result = *first1;
- ++first1;
- }
- else {
- *result = *first2;
- ++first2;
- }
- ++result;
- }
-
- if (first1==last1) {
- // list1 empty, copy rest of list2, then list3
- return copy(first3, last3, copy(first2, last2, result));
- } else {
- // list2 empty, merge rest of list1 with list3
- return mymerge(first1,last1,first3,last3,result,comp);
- }
-}
-