Useful shortcuts in Vectors

Vector Initialization: You can initialize a vector with a specified size and an initial value using the following syntax:


vector<int> v(size, initial_value);

For example:


vector<int> v(5, 0); // initialize a vector of size 5 with all elements set to 0

Vector Size: You can get the number of elements in a vector using the size() method:


int num_elements = v.size();

Pushing Elements to the Back: You can push a new element to the back of a vector using the push_back() method:


v.push_back(element);

For example:


vector<int> v;
v.push_back(5); // Add an element with value 5 to the back of the vector

Accessing Elements: You can access the elements of a vector using their index, starting from 0:


int element = v[index];

For example:


vector<int> v = {1, 2, 3, 4, 5};
int element = v[2]; // Access the element with index 2, which is 3

Finding the Largest Element: You can find the largest element in a vector using the max_element() function from the <algorithm> library:


auto it = max_element(v.begin(), v.end());
int largest_element = *it;

For example:


vector<int> v = {5, 10, 3, 7, 1};
auto it = max_element(v.begin(), v.end()); // Find the iterator to the largest element
int largest_element = *it; // Get the value of the largest element

Sorting a Vector: You can sort the elements of a vector using the sort() function from the <algorithm> library:


sort(v.begin(), v.end());

For example:


vector<int> v = {5, 10, 3, 7, 1};
sort(v.begin(), v.end()); // Sort the vector

Finding the Lower Bound: You can find the iterator to the first element that is equal to or greater than a given element using the lower_bound() function from the <algorithm> library:


auto it = lower_bound(v.begin(), v.end(), element);

For example:


vector<int> v = {1, 2, 3, 4, 5};
auto it = lower_bound(v.begin(), v.end(), 3); // Find the iterator to the first element that is >= 3

Finding the Upper Bound: You can find the iterator to the first element that is greater than a given element using the upper_bound() function from the <algorithm> library:


auto it = upper_bound(v.begin(), v.end(), element);

For example:


vector<int> v = {1, 2, 3, 4, 5};
auto it = upper_bound(v.begin(), v.end(), 3); // Find the iterator to the first element that is > 3

Note: Make sure to include the <algorithm> header file to use the above functions.

PRACTICE QUESTIONS :

Remove Duplicates from Sorted Array

Next Permutation