LevelWisePrintOfTree.cpp

/* 
Given a generic tree, print the input tree in level wise order.
For printing a node with data N, you need to follow the exact format -
N:x1,x2,x3,...,xn
where, N is data of any node present in the generic tree. x1, x2, x3, ...., xn are the children of node N. Note that there is no space in between.
Print all nodes in the level order form in different lines.
*/

/* Sample Input
10 3 20 30 40 2 40 50 0 0 0 0 
Sample Output
10:20,30,40
20:40,50
30:
40:
40:
50:
*/

// code

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

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];
        }
    }
};

void printLevelWise(TreeNode<int>* root) {
 
   queue<TreeNode<int>*>pendingnodes;
    pendingnodes.push(root);
    
    while(pendingnodes.size()!=0){
    TreeNode<int>* front = pendingnodes.front();
    pendingnodes.pop();
    cout<<front->data<<":";
         
        for(int i=0;i<front->children.size();i++){
            if(i==front->children.size()-1){
              cout<<front->children[i]->data;
            pendingnodes.push(front->children[i]);  
            }
            else{
             cout<<front->children[i]->data<<",";
             pendingnodes.push(front->children[i]);
             }
        }
      cout<<endl;
          
        }
}

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();
    printLevelWise(root);
  return 0;
}