public bool findAncestors(int search_item, CSharp.Stack.Stack <int> ancestry)
{
if (search_item == this.item)
{
ancestry.push(this.item);
return(true);
}
else
{
if (this.left_child != null && this.left_child.findAncestors(search_item, ancestry))
{
ancestry.push(this.item);
return(true);
}
else if (this.right_child != null && this.right_child.findAncestors(search_item, ancestry))
{
ancestry.push(this.item);
return(true);
}
else
{
return(false);
}
}
}
public int getDistanceBetweenNodes(int node_1_item, int node_2_item)
{
CSharp.Stack.Stack <int> node_1_ancestry = new CSharp.Stack.Stack <int>(1000);
this.root.findAncestors(node_1_item, node_1_ancestry);
CSharp.Stack.Stack <int> node_2_ancestry = new CSharp.Stack.Stack <int>(1000);
this.root.findAncestors(node_2_item, node_2_ancestry);
int min_distance = 0;
while (true)
{
if (!node_1_ancestry.isEmpty() && !node_2_ancestry.isEmpty())
{
if (node_1_ancestry.pop() != node_2_ancestry.pop())
{
min_distance += 2;
}
}
else if (!node_1_ancestry.isEmpty())
{
node_1_ancestry.pop();
min_distance++;
}
else if (!node_2_ancestry.isEmpty())
{
node_2_ancestry.pop();
min_distance++;
}
else
{
break;
}
}
return(min_distance);
}
public static string reverseWordsInString(string str)
{
string result_str = "";
CSharp.Stack.Stack <char> stack = new CSharp.Stack.Stack <char>(1000);
for (int i = 0; i < str.Length; i++)
{
char letter = str[i];
if (letter != ' ')
{
stack.push(letter);
}
if (letter == ' ' || i == str.Length - 1)
{
while (!stack.isEmpty())
{
result_str += stack.pop();
}
if (letter == ' ')
{
result_str += ' ';
}
}
}
return(result_str);
}
public static bool isExpressionBalanced(string expression)
{
CSharp.Stack.Stack <char> stack = new CSharp.Stack.Stack <char>(1000);
Dictionary <char, char> mapping = new Dictionary <char, char>();
mapping.Add('{', '}');
mapping.Add('[', ']');
mapping.Add('(', ')');
foreach (char letter in expression)
{
if (letter == '{' || letter == '(' || letter == '[')
{
stack.push(letter);
}
else if (letter == '}' || letter == ')' || letter == ']')
{
char last_keyword = stack.pop();
if (mapping[last_keyword] != letter)
{
return(false);
}
}
}
return(stack.isEmpty());
}
static void testStack()
{
CSharp.Stack.Stack <int> stack = new CSharp.Stack.Stack <int>(4);
int[] insert_items = { 3, 6, 8, 2 };
foreach (int item in insert_items)
{
stack.push(item);
}
Console.WriteLine("peek: " + stack.peek());
Console.WriteLine("pop: " + stack.pop());
Console.WriteLine("peek: " + stack.peek());
}
