next_permutation()—遍历全排列

next_permutation()--遍历全排列

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template <class BidirectionalIterator>
  bool next_permutation (BidirectionalIterator first,
                         BidirectionalIterator last);


template <class BidirectionalIterator, class Compare>
  bool next_permutation (BidirectionalIterator first,
                         BidirectionalIterator last, Compare comp);

如果可以继续遍历则返回True,否则返回False,直到数组从增序一直遍历到减序.

示例:

#include <iostream>
#include <algorithm>

using namespace std;

int main() {
  char arr[] = {'A', 'B', 'C'};
  // int arr[] = {1, 2, 3};
  // string arr[] = {"A", "B", "C"};

  sort(arr, arr+3);  
  // 排序保证数组顺序为增序,这样才可以把全排列遍历完.

  do {
    cout << arr[0] << arr[1] << arr[2] << endl;
  } while (next_permutation(arr, arr+3));

  cout << "After Loop: " << arr[0] << arr[1] << arr[2] << endl;

  return 0;
}

结果:

ABC
ACB
BAC
BCA
CAB
CBA
After Loop: ABC