private void FindAllSumPathRecursive(TreeNode<int> node, List<string> results, Stack<int> stack, int sum, int currentSum)
{
if (node == null)
{
return;
}
if (node.LeftNode == null && node.RightNode == null)
{
if (currentSum + node.Value == sum)
{
int[] array = new int[stack.Count];
stack.CopyTo(array, 0);
results.Add(node.Value + " " + string.Join(" ", array));
}
return;
}
stack.Push(node.Value);
FindAllSumPathRecursive(node.LeftNode, results, stack, sum, currentSum + node.Value);
FindAllSumPathRecursive(node.RightNode, results, stack, sum, currentSum + node.Value);
stack.Pop();
}
public int LongestValidParenthese(string input)
{
if (input == null || input.Length == 0)
{
throw new NullReferenceException("input is null");
}
Stack<int> leftParenStack = new Stack<int>();
int validNum = 0;
for (int i = 0; i < input.Length; i++)
{
if (input[i] == '(')
{
leftParenStack.Push(input[i]);
}
else if(input[i] == ')' && leftParenStack.Count != 0)
{
leftParenStack.Pop();
validNum++;
}
}
return validNum;
}