I have trying to make a clone of adjacency list in c++. But couldn't possibly do so.
I have declared using:
vector<int> adj[N]; // N is the number of vertices
How do I make the clone of this list in c++ ?
I tried looking up on the web. But couldn't find any answer. Requesting my fellow mates to answer this question.
I recommend to avoid using old c style arrays in c++ in favor of only std::vector (or std::array for static sized arrays).
Your adjacency list could be implemented using:
std::vector<std::vector<int>> adj(N);
This is using the std::vector constructor that accepts a size, and enables N to be dynamic (whereas in your code it must be known at compile time because c++ does not support VLAs - variable length arrays).
Cloning is easy:
std::vector<std::vector<int>> clone = adj;
If you must use a c style array, you can clone it with:
vector<int> clone[N];
std::copy(std::begin(adj), std::end(adj), std::begin(clone));
A side note: better to avoid using namespace std - see here Why is "using namespace std;" considered bad practice?.
vector<int> clone[N]; std::copy(std::begin(adj), std::end(adj), std::begin(clone));vector<vector<int>>instead, and, simply,adj2=adj?std::array<std::vector<int>, N>for an array of vectors andajd2=adjfor the copy.vector<int>[N]. Prefer a good book instead.