Sequential traversal of a 8:2-fork search Tree

Two fork Search tree:(also known as: two fork find tree, binary sort tree)

Satisfying nature:

(1) It is either an empty tree;

(2) or a two-fork tree having the following properties:

<1> Joz tree is not empty, the value of all nodes on the left subtree is less than the value of its root node;

<2> If the right subtree is not empty, the value of all nodes on the right subtree is greater than the value of its root node;

<3> left and right subtree are also two to find the order tree;

Problem Description:

Enter an array of integers to determine if the array is the result of a sequential traversal of a binary lookup tree. Returns False if True is returned.

Analytical:

According to the definition of post-order traversal, if a sequence is the result of a subsequent traversal of a two-fork tree, then it is not difficult to conclude that the last node of the sequence must be the root node of the two-fork tree, except for the root node, in which the first part of the sequence is the node of the left subtree of the two-tree, Similarly, the ergodic results of the left and right subtrees also have the same characteristics.

The code is as follows:

BOOL Verifysquenceofbst (int sequence[], int length)

{

if (sequence== NULL | | length <= 0)

Returnfalse;

int root =sequence[length-1];

The node of the left subtree in the binary search tree is smaller than the root node.

int i = 0;

for (; I <length-1; + + i)

{

if (Sequence[i] > root)

Break

}

The nodes of the right subtree in the binary search tree are larger than the root nodes.

int j = i;

for (; J <length-1; + + j)

{

if (Sequence[j] < root)

return false;

}

Determine if the left subtree is a binary search tree

BOOL left =true;

if (i > 0)

Left =verifysquenceofbst (sequence, i);

Judging right subtree is not binary search tree

bool Right =true;

if (i <length-1)

Right =verifysquenceofbst (sequence + i, length-i-1);

Return (left&& right);

}

Note: "Sword refers to offer" study notes

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Sequential traversal of a 8:2-fork search Tree