std::set_difference

 

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功能 Original: Functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
修改序列操作 Original: Non-modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
all_of any_of none_of （C++11） （C++11） （C++11） for_each count count_if mismatch equal	find find_if find_if_not （C++11） find_end find_first_of adjacent_find search search_n
修改序列操作 Original: Modifying sequence operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
copy copy_if （C++11） copy_n （C++11） copy_backward move （C++11） move_backward （C++11） fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   （C++11） unique unique_copy
分区操作 Original: Partitioning operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_partitioned （C++11） partition partition_copy （C++11）	stable_partition partition_point （C++11）
排序操作（排序的区间） Original: Sorting operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_sorted （C++11） is_sorted_until （C++11） sort	partial_sort partial_sort_copy stable_sort nth_element
二进制搜索操作（排序的区间） Original: Binary search operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
lower_bound upper_bound	binary_search equal_range
设置操作（排序的区间） Original: Set operations (on sorted ranges) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
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is_heap is_heap_until （C++11） make_heap	push_heap pop_heap sort_heap
最小/最大操作 Original: Minimum/maximum operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
max max_element min min_element minmax （C++11） minmax_element （C++11）	lexicographical_compare is_permutation （C++11） next_permutation prev_permutation
数字操作 Original: Numeric operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
iota （C++11） accumulate inner_product	adjacent_difference partial_sum
C库 Original: C library The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
qsort	bsearch

 

Defined in header <algorithm>
template< class InputIt1, class InputIt2, class OutputIt > OutputIt set_difference( InputIt1 first1, InputIt1 last1,                          InputIt2 first2, InputIt2 last2,                          OutputIt d_first );	(1)
template< class InputIt1, class InputIt2,           class OutputIt, class Compare > OutputIt set_difference( InputIt1 first1, InputIt1 last1,                          InputIt2 first2, InputIt2 last2,                          OutputIt d_first, Compare comp );	(2)

副本中的元素排序的范围[first1, last1)都没有发现在已排序的范围内，[first2, last2)在d_first的范围开始

Original:

Copies the elements from the sorted range [first1, last1) which are not found in the sorted range [first2, last2) to the range beginning at d_first.

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由此获得的范围也进行排序。的第一个版本预计两个输入范围与operator<，第二个版本需要进行排序的比较函数comp进行排序。等效元素单独处理，即，如果发现一些元件m次[first1, last1)n在[first2, last2)的时候，它将被复制到d_first完全相同std::max(m-n, 0)倍，由此获得的范围不能与任一输入范围重叠.

Original:

The resulting range is also sorted. The first version expects both input ranges to be sorted with operator<, the second version expects them to be sorted with the given comparison function comp. Equivalent elements are treated individually, that is, if some element is found m times in [first1, last1) and n times in [first2, last2), it will be copied to d_first exactly std::max(m-n, 0) times. The resulting range cannot overlap with either of the input ranges.

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参数

first1, last1	-	检查的元素 Original: the range of elements to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
first2, last2	-	的元素的范围搜索 Original: the range of elements to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
comp	-	comparison function which returns ​true if the first argument is less than the second. The signature of the comparison function should be equivalent to the following: bool cmp(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function must not modify the objects passed to it. The types  Type1 and  Type2 must be such that objects of types InputIt1 and InputIt2 can be dereferenced and then implicitly converted to  Type1 and  Type2 respectively. ​
Type requirements
- InputIt1 must meet the requirements of InputIterator.
- InputIt2 must meet the requirements of InputIterator.
- OutputIt must meet the requirements of OutputIterator.

返回值

过去的结尾的Iterator构建范围.

Original:

Iterator past the end of the constructed range.

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复杂性

最2·(N₁+N₂-1)比较，其中N₁= std::distance(first1, last1)和N₂= std::distance(first2, last2).

Original:

At most 2·(N₁+N₂-1) comparisons, where N₁ = std::distance(first1, last1) and N₂ = std::distance(first2, last2).

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可能的实现

First version
template<class InputIt1, class InputIt2, class OutputIt> OutputIt set_difference(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2, OutputIt d_first) { while (first1 != last1) { if (first2 == last2) return std::copy(first1, last1, d_first);   if (*first1 < *first2) { *d_first++ = *first1++; } else { if (! (*first2 < *first1)) { ++first1; } ++first2; } } return d_first; }
Second version
template<class InputIt1, class InputIt2, class OutputIt, class Compare> OutputIt set_difference( InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2, OutputIt d_first, Compare comp) { while (first1 != last1) { if (first2 == last2) return std::copy(first1, last1, d_first);   if (comp(*first1, *first2)) { *d_first++ = *first1++; } else { if (!comp(*first2, *first1)) { ++first1; } ++first2; } } return d_first; }

为例

#include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
 
int main() {
    std::vector<int> v1 {1, 2, 5, 5, 5, 9};
    std::vector<int> v2 {2, 5, 7};
    std::vector<int> diff;
 
    std::set_difference(v1.begin(), v1.end(), v2.begin(), v2.end(), 
                        std::inserter(diff, diff.begin()));
 
    for (auto i : v1) std::cout << i << ' ';
    std::cout << "minus ";
    for (auto i : v2) std::cout << i << ' ';
    std::cout << "is: ";
 
    for (auto i : diff) std::cout << i << ' ';
    std::cout << '\n';
}

Output:

1 2 5 5 5 9 minus 2 5 7 is: 1 5 5 9

另请参阅

includes	返回true，如果一组的一个子集的另一个 Original: returns true if one set is a subset of another The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）
set_symmetric_difference	计算对称的两组之间的差异 Original: computes the symmetric difference between two sets The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）