In C++, vectors are dynamic containers with the ability to resize themselves automatically when an element is inserted or deleted. In this article, we will learn how to find the last element in a vector that satisfies the given condition in C++.
Example
Input: myVector ={10, 20, 40, 20, 50, 10, 20, 30} Output: Element present at index: 6
Find the Last Element in Vector Which Satisfies a Condition
To find the last element in a vector that satisfies the given condition, we can use the std::find_if() method provided by the STL library in C++. This method will return the iterator to the matching element. We then use the std::distance() to calculate the actual index value.
C++ Program to Find the Last Element in Vector Which Satisfies a Condition
In this example, we will find the last even number in the vector container as an example.
// C++ program to illustrate how to find the last element in // vector which satisfies the given condition #include <algorithm> #include <iostream> #include <vector> using namespace std;
int main()
{ // Initialize a vector
vector< int > myVector = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
// Use reverse iterator to find the last even number
auto it = find_if(myVector.rbegin(), myVector.rend(),
[]( int num) { return num % 2 == 0; });
// checking if we found the element or not
if (it != myVector.rend()) {
cout << "The last even number in the vector is at: "
<< distance(it, myVector.rend()) - 1 << "\n" ;
}
else {
cout << "No even numbers found in the vector.\n" ;
}
return 0;
} |
The last even number in the vector is at: 7
Time Complexity: O(N), where N is the total number of elements present in the vector.
Auxilary Space: O(1)