Vertical Order Traversal of Binary Tree in DSA C++ - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a map that stores nodes by their vertical column index.

DSA C++

std::map<int, std::vector<int>> [1];

Drag options to blanks, or click blank then click option'

AverticalOrder

BnodeMap

CcolumnTable

DtreeMap

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name that does not reflect the purpose, like 'treeMap'.

Using an invalid variable name.

The variable name 'verticalOrder' clearly represents the map storing nodes by their vertical columns.

2fill in blank

medium

Complete the code to push the current node's value into the vector for its column in the map.

DSA C++

verticalOrder[[1]].push_back(node->val);

Drag options to blanks, or click blank then click option'

Arow

Bcolumn

Clevel

Dindex

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'row' or 'level' which represent vertical depth, not horizontal position.

Using an undefined variable.

We use the 'column' index to group nodes vertically in the map.

3fill in blank

hard

Fix the error in the queue push operation to add the left child with updated column and row.

DSA C++

if (node->left) q.push({node->left, [1], [2]);

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Acolumn - 1

Brow + 1

Ccolumn + 1

Drow - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping row and column updates.

Increasing column for left child.

For the left child, column decreases by 1 and row increases by 1.

4fill in blank

hard

Fill both blanks to sort nodes first by row, then by value within each column.

DSA C++

std::sort(verticalOrder[[1]].begin(), verticalOrder[[2]].end());

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Acolumn

Brow

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using different keys for begin() and end().

Sorting by row which is not stored in the vector.

We sort the vector of nodes in each column, so both blanks use 'column' as the key.

5fill in blank

hard

Fill all three blanks to build the final result vector from the map.

DSA C++

for (auto& [1] : verticalOrder) {
    result.push_back([2].second);
}
return [3];

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AcolumnPair

Cresult

DverticalOrder

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names in the loop.

Returning the map instead of the result vector.

We iterate over each columnPair in verticalOrder, push its vector to result, and return result.