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Printing Binary Trees in Ascii
/*
Copy from: http://web.archive.org/web/20090617110918/http://www.openasthra.com/c-tidbits/printing-binary-trees-in-ascii/
Source: http://web.archive.org/web/20071224095835/http://www.openasthra.com:80/wp-content/uploads/2007/12/binary_trees1.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Tree Tree;
struct Tree {
Tree *left, *right;
int element;
};
Tree *make_empty(Tree *t) {
if (t != NULL) {
make_empty(t->left);
make_empty(t->right);
free(t);
}
return NULL;
}
Tree *find_min(Tree *t) {
if (t == NULL) {
return NULL;
} else if (t->left == NULL) {
return t;
} else {
return find_min(t->left);
}
}
Tree *find_max(Tree *t) {
if (t == NULL) {
return NULL;
} else if (t->right == NULL) {
return t;
} else {
return find_max(t->right);
}
}
Tree *find(int elem, Tree *t) {
if (t == NULL) {
return NULL;
}
if (elem < t->element) {
return find(elem, t->left);
} else if (elem > t->element) {
return find(elem, t->right);
} else {
return t;
}
}
//Insert i into the tree t, duplicate will be discarded
//Return a pointer to the resulting tree.
Tree *insert(int value, Tree *t) {
Tree *new_node;
if (t == NULL) {
new_node = (Tree *) malloc(sizeof(Tree));
if (new_node == NULL) {
return t;
}
new_node->element = value;
new_node->left = new_node->right = NULL;
return new_node;
}
if (value < t->element) {
t->left = insert(value, t->left);
} else if (value > t->element) {
t->right = insert(value, t->right);
} else {
//duplicate, ignore it
return t;
}
return t;
}
Tree *delete(int value, Tree *t) {
//Deletes node from the tree
// Return a pointer to the resulting tree
Tree *x;
Tree *tmp_cell;
if (t == NULL) return NULL;
if (value < t->element) {
t->left = delete(value, t->left);
} else if (value > t->element) {
t->right = delete(value, t->right);
} else if (t->left && t->right) {
tmp_cell = find_min(t->right);
t->element = tmp_cell->element;
t->right = delete(t->element, t->right);
} else {
tmp_cell = t;
if (t->left == NULL)
t = t->right;
else if (t->right == NULL)
t = t->left;
free(tmp_cell);
}
return t;
}
//printing tree in ascii
typedef struct asciinode_struct asciinode;
struct asciinode_struct {
asciinode *left, *right;
//length of the edge from this node to its children
int edge_length;
int height;
int lablen;
//-1=I am left, 0=I am root, 1=right
int parent_dir;
//max supported unit32 in dec, 10 digits max
char label[11];
};
#define MAX_HEIGHT 1000
int lprofile[MAX_HEIGHT];
int rprofile[MAX_HEIGHT];
#define INFINITY (1<<20)
//adjust gap between left and right nodes
int gap = 3;
//used for printing next node in the same level,
//this is the x coordinate of the next char printed
int print_next;
int MIN(int X, int Y) {
return ((X) < (Y)) ? (X) : (Y);
}
int MAX(int X, int Y) {
return ((X) > (Y)) ? (X) : (Y);
}
asciinode *build_ascii_tree_recursive(Tree *t) {
asciinode *node;
if (t == NULL) return NULL;
node = malloc(sizeof(asciinode));
node->left = build_ascii_tree_recursive(t->left);
node->right = build_ascii_tree_recursive(t->right);
if (node->left != NULL) {
node->left->parent_dir = -1;
}
if (node->right != NULL) {
node->right->parent_dir = 1;
}
sprintf(node->label, "%d", t->element);
node->lablen = (int) strlen(node->label);
return node;
}
//Copy the tree into the ascii node structre
asciinode *build_ascii_tree(Tree *t) {
asciinode *node;
if (t == NULL) return NULL;
node = build_ascii_tree_recursive(t);
node->parent_dir = 0;
return node;
}
//Free all the nodes of the given tree
void free_ascii_tree(asciinode *node) {
if (node == NULL) return;
free_ascii_tree(node->left);
free_ascii_tree(node->right);
free(node);
}
//The following function fills in the lprofile array for the given tree.
//It assumes that the center of the label of the root of this tree
//is located at a position (x,y). It assumes that the edge_length
//fields have been computed for this tree.
void compute_lprofile(asciinode *node, int x, int y) {
int i, isleft;
if (node == NULL) return;
isleft = (node->parent_dir == -1);
lprofile[y] = MIN(lprofile[y], x - ((node->lablen - isleft) / 2));
if (node->left != NULL) {
for (i = 1; i <= node->edge_length && y + i < MAX_HEIGHT; i++) {
lprofile[y + i] = MIN(lprofile[y + i], x - i);
}
}
compute_lprofile(node->left, x - node->edge_length - 1, y + node->edge_length + 1);
compute_lprofile(node->right, x + node->edge_length + 1, y + node->edge_length + 1);
}
void compute_rprofile(asciinode *node, int x, int y) {
int i, notleft;
if (node == NULL) return;
notleft = (node->parent_dir != -1);
rprofile[y] = MAX(rprofile[y], x + ((node->lablen - notleft) / 2));
if (node->right != NULL) {
for (i = 1; i <= node->edge_length && y + i < MAX_HEIGHT; i++) {
rprofile[y + i] = MAX(rprofile[y + i], x + i);
}
}
compute_rprofile(node->left, x - node->edge_length - 1, y + node->edge_length + 1);
compute_rprofile(node->right, x + node->edge_length + 1, y + node->edge_length + 1);
}
//This function fills in the edge_length and
//height fields of the specified tree
void compute_edge_lengths(asciinode *node) {
int h, hmin, i, delta;
if (node == NULL) return;
compute_edge_lengths(node->left);
compute_edge_lengths(node->right);
/* first fill in the edge_length of node */
if (node->right == NULL && node->left == NULL) {
node->edge_length = 0;
} else {
if (node->left != NULL) {
for (i = 0; i < node->left->height && i < MAX_HEIGHT; i++) {
rprofile[i] = -INFINITY;
}
compute_rprofile(node->left, 0, 0);
hmin = node->left->height;
} else {
hmin = 0;
}
if (node->right != NULL) {
for (i = 0; i < node->right->height && i < MAX_HEIGHT; i++) {
lprofile[i] = INFINITY;
}
compute_lprofile(node->right, 0, 0);
hmin = MIN(node->right->height, hmin);
} else {
hmin = 0;
}
delta = 4;
for (i = 0; i < hmin; i++) {
delta = MAX(delta, gap + 1 + rprofile[i] - lprofile[i]);
}
//If the node has two children of height 1, then we allow the
//two leaves to be within 1, instead of 2
if (((node->left != NULL && node->left->height == 1) ||
(node->right != NULL && node->right->height == 1)) && delta > 4) {
delta--;
}
node->edge_length = ((delta + 1) / 2) - 1;
}
//now fill in the height of node
h = 1;
if (node->left != NULL) {
h = MAX(node->left->height + node->edge_length + 1, h);
}
if (node->right != NULL) {
h = MAX(node->right->height + node->edge_length + 1, h);
}
node->height = h;
}
//This function prints the given level of the given tree, assuming
//that the node has the given x cordinate.
void print_level(asciinode *node, int x, int level) {
int i, isleft;
if (node == NULL) return;
isleft = (node->parent_dir == -1);
if (level == 0) {
for (i = 0; i < (x - print_next - ((node->lablen - isleft) / 2)); i++) {
printf(" ");
}
print_next += i;
printf("%s", node->label);
print_next += node->lablen;
} else if (node->edge_length >= level) {
if (node->left != NULL) {
for (i = 0; i < (x - print_next - (level)); i++) {
printf(" ");
}
print_next += i;
printf("/");
print_next++;
}
if (node->right != NULL) {
for (i = 0; i < (x - print_next + (level)); i++) {
printf(" ");
}
print_next += i;
printf("\\");
print_next++;
}
} else {
print_level(node->left,
x - node->edge_length - 1,
level - node->edge_length - 1);
print_level(node->right,
x + node->edge_length + 1,
level - node->edge_length - 1);
}
}
//prints ascii tree for given Tree structure
void print_ascii_tree(Tree *t) {
asciinode *proot;
int xmin, i;
if (t == NULL) return;
proot = build_ascii_tree(t);
compute_edge_lengths(proot);
for (i = 0; i < proot->height && i < MAX_HEIGHT; i++) {
lprofile[i] = INFINITY;
}
compute_lprofile(proot, 0, 0);
xmin = 0;
for (i = 0; i < proot->height && i < MAX_HEIGHT; i++) {
xmin = MIN(xmin, lprofile[i]);
}
for (i = 0; i < proot->height; i++) {
print_next = 0;
print_level(proot, -xmin, i);
printf("\n");
}
if (proot->height >= MAX_HEIGHT) {
printf("(This tree is taller than %d, and may be drawn incorrectly.)\n", MAX_HEIGHT);
}
free_ascii_tree(proot);
}
//driver routine
int main() {
//A sample use of these functions. Start with the empty tree
//insert some stuff into it, and then delete it
Tree *root;
int i;
root = NULL;
make_empty(root);
printf("\nAfter inserting element 10..\n");
root = insert(10, root);
print_ascii_tree(root);
printf("\nAfter inserting element 5..\n");
root = insert(5, root);
print_ascii_tree(root);
printf("\nAfter inserting element 15..\n");
root = insert(15, root);
print_ascii_tree(root);
printf("\nAfter inserting elements 9, 13..\n");
root = insert(9, root);
root = insert(13, root);
print_ascii_tree(root);
printf("\nAfter inserting elements 2, 6, 12, 14, ..\n");
root = insert(2, root);
root = insert(6, root);
root = insert(12, root);
root = insert(14, root);
print_ascii_tree(root);
printf("\n\nAfter deleting a node (14) with no child..\n");
root = delete(14, root);
print_ascii_tree(root);
printf("\n\nAfter deleting a node (13) with left child..\n");
root = delete(13, root);
print_ascii_tree(root);
printf("\n\nAfter deleting a node (5) with left and right children..\n");
root = delete(5, root);
print_ascii_tree(root);
printf("\n\nAfter deleting a node (10, root node) with left and right children..\n");
root = delete(10, root);
print_ascii_tree(root);
make_empty(root);
return 0;
}
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