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April 23, 2017 16:14
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#include <stdlib.h> | |
#include <stdio.h> | |
typedef struct node_s | |
{ | |
int value; | |
struct node_s* left; | |
struct node_s* right; | |
} *node; | |
node tree(int v, node l, node r) | |
{ | |
node n = malloc(sizeof(struct node_s)); | |
n->value = v; | |
n->left = l; | |
n->right = r; | |
return n; | |
} | |
void destroy_tree(node n) | |
{ | |
if (n->left) | |
destroy_tree(n->left); | |
if (n->right) | |
destroy_tree(n->right); | |
free(n); | |
} | |
void preorder(node n, void (*f)(int)) | |
{ | |
f(n->value); | |
if (n->left) | |
preorder(n->left, f); | |
if (n->right) | |
preorder(n->right, f); | |
} | |
void inorder(node n, void (*f)(int)) | |
{ | |
if (n->left) | |
inorder(n->left, f); | |
f(n->value); | |
if (n->right) | |
inorder(n->right, f); | |
} | |
void postorder(node n, void (*f)(int)) | |
{ | |
if (n->left) | |
postorder(n->left, f); | |
if (n->right) | |
postorder(n->right, f); | |
f(n->value); | |
} | |
/* helper queue for levelorder */ | |
typedef struct qnode_s | |
{ | |
struct qnode_s* next; | |
node value; | |
} *qnode; | |
typedef struct { qnode begin, end; } queue; | |
void enqueue(queue* q, node n) | |
{ | |
qnode node = malloc(sizeof(struct qnode_s)); | |
node->value = n; | |
node->next = 0; | |
if (q->end) | |
q->end->next = node; | |
else | |
q->begin = node; | |
q->end = node; | |
} | |
node dequeue(queue* q) | |
{ | |
node tmp = q->begin->value; | |
qnode second = q->begin->next; | |
free(q->begin); | |
q->begin = second; | |
if (!q->begin) | |
q->end = 0; | |
return tmp; | |
} | |
int queue_empty(queue* q) | |
{ | |
return !q->begin; | |
} | |
void levelorder(node n, void(*f)(int)) | |
{ | |
queue nodequeue = {}; | |
enqueue(&nodequeue, n); | |
while (!queue_empty(&nodequeue)) | |
{ | |
node next = dequeue(&nodequeue); | |
f(next->value); | |
if (next->left) | |
enqueue(&nodequeue, next->left); | |
if (next->right) | |
enqueue(&nodequeue, next->right); | |
} | |
} | |
void print(int n) | |
{ | |
printf("%d ", n); | |
} | |
int main() | |
{ | |
node n = tree(1, | |
tree(2, | |
tree(4, | |
tree(7, 0, 0), | |
0), | |
tree(5, 0, 0)), | |
tree(3, | |
tree(6, | |
tree(8, 0, 0), | |
tree(9, 0, 0)), | |
0)); | |
printf("preorder: "); | |
preorder(n, print); | |
printf("\n"); | |
printf("inorder: "); | |
inorder(n, print); | |
printf("\n"); | |
printf("postorder: "); | |
postorder(n, print); | |
printf("\n"); | |
printf("level-order: "); | |
levelorder(n, print); | |
printf("\n"); | |
destroy_tree(n); | |
return 0; | |
} |
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