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#include<stdlib.h>
#include<stdio.h>
#include <string.h>
typedef struct anode {
char *name;
struct anode *r, *l;
} node;
node* contains(tree, q)
node **tree;
char *q;
{
node *tmp;
if(!(*tree)) return 0;
if ( strcmp((*tree)->name, q) == 0){
return *tree;
}
tmp = contains(&(*tree)->l, q);
return tmp ? tmp : contains(&(*tree)->r, q);
}
insert(tree, item)
node **tree;
node *item;
{
if(!(*tree)) {
*tree = item;
return 1;
}
if(strcmp(item->name, (*tree)->name) < 0)
insert(&(*tree)->l, item);
else if(strcmp(item->name, (*tree)->name) > 0)
insert(&(*tree)->r, item);
}
node* getParent(tree,item)
node **tree;
node *item;
{
node *tmp;
if(!(*tree)) return 0;
if(*tree == item)
return -1;
if((*tree)->l == item || (*tree)->r == item)
return *tree;
tmp = getParent(&(*tree)->l, item);
return tmp ? tmp : getParent(&(*tree)->r, item);
}
delete(tree, item)
node **tree;
node *item;
{
node *tmp, *parent, *tmp_parent;
int cnt;
if(!(*tree)) return 1;
tmp = contains(tree, item->name);
if(!tmp){
printf("%s dose not exist\n", item->name);
return 1;
}
parent = getParent(tree, tmp);
if(!tmp->l && !tmp->r)
{
if (parent == -1){
*tree = 0;
return 1;
free(tmp);
}
if(parent->l == tmp){
parent->l = 0;
free(tmp);
return 1;
}
parent->r = 0;
free(tmp);
return 1;
}
if(tmp->l && tmp->r){
item = tmp->r;
while(item->l)
item = item->l;
tmp_parent = getParent(tree, item);
if(parent == -1){
*tree = item;
item->l = tmp->l;
item->r = tmp->r;
if(tmp_parent == tmp)
item->r = 0;
else
tmp_parent->l = 0;
tree = &item;
free(tmp);
return 1;
}
if(parent->l == tmp){
parent->l = item;
item->l = tmp->l;
item->r = tmp->r;
if(tmp_parent == tmp)
item->r = 0;
else
tmp_parent->l = 0;
tree = &item;
free(tmp);
return 1;
}
parent->r = item;
item->l = tmp->l;
item->r = tmp->r;
if(tmp_parent == tmp)
item->r = 0;
else
tmp_parent->l = 0;
tree = &item;
free(tmp);
return 1;
}
if (parent == -1) {
*tree = tmp->l ? tmp->l : tmp->r;
free(tmp);
return 1;
}
if(parent->l == tmp){
parent->l = tmp->l ? tmp->l : tmp->r;
free(tmp);
return 1;
}
parent->r = tmp->l ? tmp->l : tmp->r;
return 1;
}
void printTree(tree)
node **tree;
{
if (!(* tree)) return;
printTree(&(*tree)->l);
printTree(&(*tree)->r);
printf("\t%s\n",(*tree)->name);
return;
}
/*
The loop below reads from stdin until EOF, then searches
to see if the BST contains the word found in argv[1].
Modify the loop to read a series of lines of one of two types:
i value
d value
Lines starting with the ASCII i are to be inserted into the binary search tree.
Those beginning with 'd' are to be deleted if they exist. If they do not exist,
output a line of text saying so and do nothing else.
Stop your read loop at EOF (like it is now). Instead of
calling contains(), print out the tree; make it a preorder print */
void main(argc, argv, envp)
int argc;
char **argv, **envp;
{
int i;
char buf[1024];
node *curr, *root;
root = 0;
while (gets(buf)) {
curr = (node *)malloc(sizeof(node));
curr->l = curr->r = NULL;
curr->name = strdup(buf + 2);
if('i' == *buf){
printf("insert: %s %s\n", buf, curr->name);
insert(&root, curr);
}
else if('d' == *buf){
printf("delete:%s %s\n", buf, curr->name);
delete(&root, curr);
}
else if ('p' == *buf)
printTree(&root);
}
printTree(&root);
}
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