RESULT tree_sum(int sum)
{
int ch, n;
RESULT left, right;
/* discard open-parenthesis */
discard_space(), getchar();
discard_space();
ch = getchar();
if(isdigit(ch) || ch == '-' || ch == '+')
{
ungetc(ch, stdin);
scanf("%d", &n);
left = tree_sum(sum - n);
right = tree_sum(sum - n);
/* discard closed-parenthesis */
discard_space(), getchar();
if(left == EMPTY && right == EMPTY && sum == n)
return YES_PATH;
else if(left == YES_PATH || right == YES_PATH)
return YES_PATH;
return NO_PATH;
}
return EMPTY;
}
int main()
{
int s;
while(scanf("%d", &s) > 0)
{
if(tree_sum(s) == YES_PATH)
printf("yes\n");
else
printf("no\n");
}
return 0;
}
int main(int argc, const char *argv[])
{
tree l = new_tree(10,
new_tree(8,
new_tree(6,
new_tree(-4, NULL, NULL),
new_tree(-2, NULL, NULL)),
NULL),
new_tree(8,
new_tree(6,
NULL,
NULL),
NULL));
tree_print(l);
printf("\n\n");
tree_iterative_traverse(print_int, l);
tree_clear_zero_sum(l);
tree_print(l);
printf("\n\n");
printf("%i\n", tree_sum(l->left->left));
return 0;
}
int tree_sum(tree_t tree) {
if (tree_isEmpty(tree)) return 0;
return tree_elt(tree) + tree_sum(tree_left(tree)) + tree_sum(tree_right(tree));
}
bool tree_zero_sum(tree xs) { // {{{
return tree_sum(xs) == 0;
} // }}}
int tree_sum(tree xs) { // {{{
if (tree_empty(xs)) return 0;
return xs->value + tree_sum(xs->left) + tree_sum(xs->right);
} // }}}
