Difference between vector V[] and vector< vector> > V

Question

vector V[] and vector< vector > V both are 2D array.

But what is the differenc

Answer 1

vector> v(26); is a vector containing vectors. In this example, you have a vector with 26 vectors contained in it. The code v[1].push_back(x) means that x is pushed back to the first vector within the vectors.

vector a[26]; is an array of vectors. In other words, a one-dimensional array containing 26 vectors of integers. The code a[1].push_back(x); has x being pushed back to the first index of the array.