## Google Interview Question

SDE-2s**Country:**United States

My finding..

1) the number of subtrees of a node is called degree of the node.

2) The degree of a tree is the maximum degree of a node in the tree.

3) A binary tree is degree 2.

then i would to this

1) review all subtree of each node with BFS

2) have one variable to keep updating max num of subtree

3) once complete to review all nodes, then return max num which would be *degree* of the graph or tree

```
struct AdjList{
unordered_map<int,vector<int> > nodes;
void insert(int i, int j){
nodes[i].push_back(j);
nodes[j].push_back(i);
}
vector<int> &getAllNeighbors(int n){
return nodes[n];
}
};
int findNodeWithDegree(int n, AdjList &adjList){
unordered_map<int,int> counts;
auto bfs = [&](int node){
deque<int> q;
counts[node] = 0;
q.push_back(node);
while(!q.empty()){
auto front = q.front();
q.pop_front();
for(auto &other : adjList.getAllNeighbors(front)){
if(counts.find(other) == counts.end()){
q.push_back(other);
}
counts[other]++;
}
}
};
for(auto &a : adjList.nodes){
if(counts.find(a.first) == counts.end()){
bfs(a.first);
}
}
for(auto &p : counts){
if(p.second == n){
return p.first;
}
}
return -1;
}
int main() {
AdjList adj;
adj.insert(0,1);
adj.insert(0,2);
adj.insert(0,3);
adj.insert(1,2);
adj.insert(1,4);
adj.insert(1,5);
adj.insert(4,5);
adj.insert(2,4);
adj.insert(2,5);
adj.insert(2,3);
adj.nodes[6] = vector<int>();
cout << findNodeWithDegree(5,adj) << endl;
return 0;
}
```

Though the code to calculate vertex degree depends on the implementation of Graph data structure, here is a simple method to calculate a degree of a vertex.

We return TRUE if any of the vertex has a degree equal to N.

```
public static int degree(Graph G, int v)
{
int degree = 0;
for (int w : G.adj(v)) degree++;
return degree;
}
```

Traverse the graph with DFS\BFS

- Anonymous October 14, 2018For each node check its degree (get the neighbors, if it is its own neighbor, i.e. cycle, add another one)