one-file-projects/binarytree.c
2017-10-12 07:12:54 +02:00

159 lines
3.7 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
typedef struct s_node {
int element;
struct s_node* left;
struct s_node* right;
} *Nodeptr, Node;
typedef Nodeptr* Tree;
Tree tree_create() {
Tree t = malloc(sizeof( Nodeptr ));
*t = NULL;
return t;
}
void tree_add(Tree t, int element) {
Nodeptr n = malloc(sizeof(Node));
n->element = element;
n->left = NULL;
n->right = NULL;
if(*t == NULL) {
*t = n;
} else {
Nodeptr iter = *t;
while(1) {
if(iter->element > element) {
if(iter->left == NULL) {
iter->left = n;
return;
} else {
iter = iter->left;
}
} else if(iter->element < element) {
if(iter->right == NULL) {
iter->right = n;
return;
} else {
iter = iter->right;
}
} else {
free(n);
return;
}
}
}
}
void tree_remove(Tree t, int element) {
Nodeptr iter = *t;
Nodeptr parent = NULL;
while(iter != NULL) {
if(iter->element > element) {
parent = iter;
iter = iter->left;
} else if(iter->element < element) {
parent = iter;
iter = iter->right;
} else {
break;
}
}
if(iter == NULL) return; // Not found
if(iter->right == NULL) {
if(parent == NULL) *t = iter->left;
else if(parent->left == iter) parent->left = iter->left;
else if(parent->right == iter) parent->right = iter->left;
else assert(0);
free(iter);
} else if(iter->left == NULL) {
if(parent == NULL) *t = iter->right;
else if(parent->left == iter) parent->left = iter->right;
else if(parent->right == iter) parent->right = iter->right;
else assert(0);
free(iter);
} else {
Nodeptr iter2, parent2;
iter2 = iter->left;
parent2 = NULL;
while(iter2->right != NULL) {
parent2 = iter2;
iter2 = iter2->right;
}
if(parent2 == NULL) {
iter->left = iter2->left;
} else {
parent2->right = iter2->left;
}
iter->element = iter2->element;
free(iter2);
}
}
int tree_contains(Tree t, int element) {
Nodeptr iter = *t;
while(iter != NULL) {
if(iter->element > element) {
iter = iter->left;
} else if(iter->element < element) {
iter = iter->right;
} else {
return 1;
}
}
return 0;
}
void tree_print_node_rec(Nodeptr n, int level) {
if(n == NULL) return;
tree_print_node_rec(n->right,level+1);
for(int i = 0; i < level; i++) printf("\t");
printf("%d\n", n->element);
tree_print_node_rec(n->left, level+1);
}
void tree_print(Tree t) {
tree_print_node_rec(*t, 0);
printf("----------\n");
}
void tree_nodefree_rec(Nodeptr n) {
if(n == NULL) return;
tree_nodefree_rec(n->left);
tree_nodefree_rec(n->right);
free(n);
}
void tree_free(Tree t) {
tree_nodefree_rec(*t);
free(t);
}
int main( int argc, char *argv[] ) {
int data[10] = {5,7,2,8,6,4,3,1,9,0};
Tree t = tree_create();
for(int i = 0; i < 10; i++) {
tree_add(t,data[i]);
}
tree_print(t);
for(int i = 0; i < 10; i++) {
assert(tree_contains(t,data[i]));
}
for(int i = 0; i < 5; i++) {
tree_remove(t,data[i]);
}
tree_print(t);
for(int i = 5; i < 10; i++) {
assert(tree_contains(t,data[i]));
}
tree_free(t);
return 0;
}