Q. Create a tree from following traversing sequence of a tree.

Pre-order – 1 2 3 4 5 6 7

In-order – 4 2 5 1 6 3 7

Post-order – 4 5 2 6 7 3 1

Answer: To create a tree form traversing sequence we compare pre-order and in-order or post-order and in-order.

1. First take one item form pre-order (1), make it root (in in-order traverse 1^st item is always is root)
2. Choose 2^nd item (2), check this item in in-order traverse where it is; left or right side, make child of root as its position in in-order.
3. Now take next item (3), again check its position in in-order traverse, put in tree as its position.

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