binarytree.c
6.7 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
#include <stdio.h>
#include <stdlib.h>
struct element
{
int data;
struct element * parent;
struct element * left;
struct element * right;
};
struct element *
newElement(int data)
{
struct element * el = malloc(sizeof(struct element));
el->data = data;
el->parent = NULL;
el->left = NULL;
el->right = NULL;
return el;
}
/**
* find element in tree
*/
struct element *
findElement(struct element * tree, int data)
{
while (NULL != tree) {
if (tree->data == data) {
break;
}
if (data < tree->data) {
tree = tree->left;
} else {
tree = tree->right;
}
}
return tree;
}
/**
* insert element in tree
*/
void
insertElement(struct element ** tree, int data)
{
struct element * node = *tree;
if (NULL == node) {
*tree = newElement(data);
return;
}
while (data != node->data) {
if (data < node->data) {
if (NULL == node->left) {
node->left = newElement(data);
node->left->parent = node;
return;
} else {
node = node->left;
}
} else {
if (NULL == node->right) {
node->right = newElement(data);
node->right->parent = node;
return;
} else {
node = node->right;
}
}
}
}
/**
* delete element from tree
* here multiple functions are involved....
* =======================================================================
*/
/**
* find minimum of the right subtree aka leftmost leaf of right subtree
* aka left in-order successor.
* We return the parent of the element in the out argument parent.
* This can be NULL wenn calling.
*/
struct element *
findInOrderSuccessor(struct element * tree)
{
struct element * node = tree->right;
while (NULL != node->left) {
node = node->left;
}
return node;
}
void
deleteElement(struct element ** tree, int data)
{
struct element * node = *tree;
// find the relevant node and it's parent
while (NULL != node && node->data != data) {
if (data < node->data) {
node = node->left;
} else {
node = node->right;
}
}
// element not found
if (NULL == node) {
return;
}
// distinuish 3 cases, where the resolving of each case leads to the
// precondition of the other.
// case 1: two children
if (NULL != node->left && NULL != node->right) {
struct element * successor = findInOrderSuccessor(node);
node->data = successor->data;
node = successor;
}
// case 2: one child wither left or right
if (NULL != node->left) {
//node->data = node->left->data;
//node = node->left;
if (NULL != node->parent) {
if (node == node->parent->left) {
node->parent->left = node->left;
} else {
node->parent->right = node->left;
}
}
node->left->parent = node->parent;
}
if (NULL != node->right) {
//node->data = node->right->data;
//node = node->right;
if (NULL != node->parent) {
if (node == node->parent->left) {
node->parent->left = node->right;
} else {
node->parent->right = node->right;
}
}
node->right->parent = node->parent;
}
// case 3: we are a leaf
if (NULL != node->parent) {
if (node == node->parent->left) {
node->parent->left = NULL;
} else {
node->parent->right = NULL;
}
}
if (node == *tree) {
if (NULL != node->left) {
*tree = node->left;
} else if (NULL != node->right) {
*tree = node->right;
} else {
*tree = NULL;
}
}
free(node);
}
void
traverse(struct element * tree, void (*cb)(int, int))
{
struct element * previous = tree;
struct element * node = tree;
int depth = 1;
/*
* I think this has something like O(n+log(n)) on a ballanced
* tree because I have to traverse back the rightmost leaf to
* the root to get a break condition.
*/
while (node) {
/*
* If we come from the right so nothing and go to our
* next parent.
*/
if (previous == node->right) {
previous = node;
node = node->parent;
depth--;
continue;
}
if ((NULL == node->left || previous == node->left)) {
/*
* If there are no more elements to the left or we
* came from the left, process data.
*/
cb(node->data, depth);
previous = node;
if (NULL != node->right) {
node = node->right;
depth++;
} else {
node = node->parent;
depth--;
}
} else {
/*
* if there are more elements to the left go there.
*/
previous = node;
node = node->left;
depth++;
}
}
}
void printElement(int data, int depth)
{
int i;
printf("%02d(%02d)", data, depth);
for (i=0; i<depth; i++) printf("-");
puts("");
}
/**
* =======================================================================
*/
int
main(int argc, char * argv[])
{
struct element * root = NULL;
insertElement(&root, 13);
insertElement(&root, 8);
insertElement(&root, 16);
insertElement(&root, 11);
insertElement(&root, 3);
insertElement(&root, 9);
insertElement(&root, 12);
insertElement(&root, 10);
/*
* delete does not work correctly here..
* luckily I do not need the simple binary trees anymore
* as I have rbtrees.
*/
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 8);
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 11);
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 13);
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 3);
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 16);
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 10);
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 9);
puts("traverse");
traverse(root, printElement);
deleteElement(&root, 12);
puts("traverse");
traverse(root, printElement);
return 0;
}
// vim: set et ts=4 sw=4: