How to write a program , Put an ordered array of integers into a binary tree ?
analysis : This paper investigates the construction method of binary search tree , Simple recursive structure .
The algorithm design of tree must be associated with recursion , Because the tree itself is the definition of recursion .
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
struct btree {
struct btree *left;
struct btree *right;
int value;
};
void create_btree(struct btree **rt, int *arr, int r, int l)
{
int pos;
struct btree *root;
if (r > l) {
*rt = NULL;
return;
}
pos = (r + l) / 2;
root = (struct btree *)malloc(sizeof(struct btree));
assert(root != NULL);
root->value = arr[pos];
*rt = root;
create_btree(&(root->left), arr, r, pos - 1);
create_btree(&(root->right), arr, pos + 1, l);
}
int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
/*
* 5
* 3 8
*
*/
void display_btree(struct btree *root)
{
if (root == NULL) {
return;
}
display_btree(root->left);
printf("%d ", root->value);
display_btree(root->right);
}
int main()
{
struct btree *root = NULL;
create_btree(&root, A, 0, 9);
printf("----------------------\n");
display_btree(root);
printf("\n----------------------\n");
return 0;
}
Technology