reverse() is a predefined function in header file algorithm. It is defined as a template in the above mentioned header file. It reverses the order of the elements in the range [first, last) of any container. The time complexity is O(n).
Note: The range used is [first, last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
void reverse(BidirectionalIterator first, BidirectionalIterator last) BidirectionalIterator is an iterator that can be used to access any elements of a container in both forward and backward direction.
Input : 10 11 12 13 14 15 16 17 Output :10 11 12 13 14 17 16 15 Explanation: reverse(v.begin() + 5, v.begin() + 8); In the above function, input we have applied reverse() on the vector from index 5 to index 7. Therefore when we display the vector we get reverse order from index 5 to index 7.
Initial Vector: 10 11 12 13 14 15 16 17 Reverse only from index 5 to 7 in vector: 10 11 12 13 14 17 16 15 Initial Vector: 4 5 6 7 Reverse full Vector: 7 6 5 4
Time complexity: O(n)
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