# Remove all leaf nodes from a Generic Tree or N-ary Tree

Given a Generic tree, the task is to delete the leaf nodes from the tree.

Examples:

```Input:
5
/  /  \  \
1   2   3   8
/   / \   \
15  4   5   6

Output:
5 : 1 2 3
1 :
2 :
3 :

Explanation:
Deleted leafs are:
8, 15, 4, 5, 6

Input:
8
/    |    \
9      7       2
/ | \    |    / / | \ \
4  5 6    10  11 1 2  2 3
Output:
8: 9 7 2
9:
7:
2:
```

Approach: Follow the steps given below to solve the problem

• Take tree into the vector.
• Traverse the tree and check the condition:
• If current node is leaf then
• Delete the leaf from vector
• Else
• Recursively call for every child.

Below is the implementation of the above approach:

 `// C++ program to delete the ` `// leaf from the generic tree ` ` `  `#include ` `using` `namespace` `std; ` ` `  `// a treenode class ` `class` `TreeNode { ` `public``: ` `    ``int` `data; ` `    ``vector children; ` ` `  `    ``TreeNode(``int` `data) ` `    ``{ ` `        ``this``->data = data; ` `    ``} ` `}; ` ` `  `// Recursive function which delete ` `// the leaf from tree ` `void` `removeLeaf(TreeNode* root) ` `{ ` `    ``// if root->children is a leaf node ` `    ``// then delete it from children vector ` `    ``for` `(``int` `i = 0; ` `         ``i < root->children.size(); ` `         ``i++) { ` ` `  `        ``TreeNode* child ` `            ``= root->children[i]; ` ` `  `        ``// if it is  a leaf ` `        ``if` `(child->children.size() == 0) { ` ` `  `            ``// shifting the vector to left ` `            ``// after the point i ` `            ``for` `(``int` `j = i; ` `                 ``j < root->children.size(); ` `                 ``j++) ` `                ``root->children[j] ` `                    ``= root->children[j + 1]; ` ` `  `            ``// delete the last element ` `            ``root->children.pop_back(); ` ` `  `            ``i--; ` `        ``} ` `    ``} ` ` `  `    ``// Remove all leaf node ` `    ``// of children of root ` `    ``for` `(``int` `i = 0; ` `         ``i < root->children.size(); ` `         ``i++) { ` ` `  `        ``// call function for root->children ` `        ``removeLeaf(root->children[i]); ` `    ``} ` `} ` ` `  `// Function which will print the ` `// tree level wise ` `void` `printTheTree(TreeNode* root) ` `{ ` `    ``if` `(root == NULL) ` `        ``return``; ` ` `  `    ``cout << root->data << ``" "` `         ``<< ``":"``; ` `    ``for` `(``int` `i = 0; ` `         ``i < root->children.size(); ` `         ``i++) ` `        ``cout << root->children[i]->data ` ` `  `             ``<< ``" "``; ` `    ``cout << endl; ` ` `  `    ``for` `(``int` `i = 0; ` `         ``i < root->children.size(); ` `         ``i++) ` `        ``printTheTree(root->children[i]); ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``// 5 ` `    ``//      / / \ \ ` `    ``// 1  2  3  8 ` `    ``//    /   /\  \ ` `    ``// 15  4  5  6 ` ` `  `    ``TreeNode* root = ``new` `TreeNode(5); ` `    ``TreeNode* child1 = ``new` `TreeNode(1); ` `    ``root->children.push_back(child1); ` `    ``TreeNode* child11 = ``new` `TreeNode(15); ` `    ``child1->children.push_back(child11); ` `    ``TreeNode* child2 = ``new` `TreeNode(2); ` `    ``root->children.push_back(child2); ` `    ``TreeNode* child21 = ``new` `TreeNode(4); ` `    ``TreeNode* child22 = ``new` `TreeNode(5); ` `    ``child2->children.push_back(child21); ` `    ``child2->children.push_back(child22); ` `    ``TreeNode* child3 = ``new` `TreeNode(3); ` `    ``root->children.push_back(child3); ` `    ``TreeNode* child31 = ``new` `TreeNode(6); ` `    ``child3->children.push_back(child31); ` `    ``TreeNode* child4 = ``new` `TreeNode(8); ` `    ``root->children.push_back(child4); ` ` `  `    ``removeLeaf(root); ` `    ``printTheTree(root); ` `}`

Output:
```5 :1 2 3
1 :
2 :
3 :
```

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