public static int Helper(LeetCode671TreeNode root, int min)
{
if (root.val != min)
{
return(root.val);
}
if (root.left == null)
{
return(-1);
}
var left = Helper(root.left, root.val);
var right = Helper(root.right, root.val);
if (left == -1)
{
return(right);
}
if (right == -1)
{
return(left);
}
return(Math.Min(left, right));
}
public static int FindSecondMinimumValue(LeetCode671TreeNode root)
{
if (root == null || root.left == null)
{
return(-1);
}
var left = Helper(root.left, root.val);
var right = Helper(root.right, root.val);
if (left == -1)
{
return(right);
}
if (right == -1)
{
return(left);
}
return(Math.Min(left, right));
}
public static int FindSecondMinimumValueV2(LeetCode671TreeNode root)
{
return(Dfs(root, root.val));
}
public LeetCode671TreeNode(int val = 0, LeetCode671TreeNode left = null, LeetCode671TreeNode right = null)
{
this.val = val;
this.left = left;
this.right = right;
}
