SumOfAllNodes.cpp

/*
Given a generic tree, count and return the sum of all nodes present in the given tree.
Input format :

Elements in level order form separated by space (as per done in class). Order is - 
Root_data, n (No_Of_Child_Of_Root), n children, and so on for every element 

Output Format :

Sum of all nodes

Sample Input :

10 3 20 30 40 2 40 50 0 0 0 0 

Sample Output :

190

 */

#include <iostream>
using namespace std;
#include <vector>

template <typename T>
class TreeNode {
public:
    T data;
    vector<TreeNode<T>*> children;
    
    TreeNode(T data) {
        this->data = data;
    }
    
    ~TreeNode() {
        for (int i = 0; i < children.size(); i++) {
            delete children[i];
        }
    }
    
};

int sumOfNodes(TreeNode<int>* root) {
    /* Don't write main().
     * Don't read input, it is passed as function argument.
     * Return output and don't print it.
     * Taking input and printing output is handled automatically. 
     */
    int ans=root->data;
    for(int i=0;i<root->children.size();i++)
        ans+=sumOfNodes(root->children[i]);
    return ans;
    
}

#include <queue>

TreeNode<int>* takeInputLevelWise() {
    int rootData;
    cin >> rootData;
    TreeNode<int>* root = new TreeNode<int>(rootData);
    
    queue<TreeNode<int>*> pendingNodes;
    
    pendingNodes.push(root);
    while (pendingNodes.size() != 0) {
        TreeNode<int>* front = pendingNodes.front();
        pendingNodes.pop();
        int numChild;
        cin >> numChild;
        for (int i = 0; i < numChild; i++) {
            int childData;
            cin >> childData;
            TreeNode<int>* child = new TreeNode<int>(childData);
            front->children.push_back(child);
            pendingNodes.push(child);
        }
    }
    return root;
}

int main() {
    TreeNode<int>* root = takeInputLevelWise();
    cout << sumOfNodes(root) << endl;
}