public void Given_Tree_When_FindLargestValues_Then_ShouldReturnLargestValues()
{
//Given
var problem = new Leetcode_515_FindLargestValueInEachTreeRow_V1();
var expectedResult = new int[] { 1, 3, 7 };
var tree = new TreeNode515(1);
var node11 = new TreeNode515(2);
var node12 = new TreeNode515(3);
tree.Left = node11;
tree.Right = node12;
var node21 = new TreeNode515(4);
var node22 = new TreeNode515(5);
node11.Left = node21;
node11.Right = node22;
var node23 = new TreeNode515(6);
var node24 = new TreeNode515(7);
node12.Left = node23;
node12.Right = node24;
//When
var actualResult = problem.FindLargestValues(tree);
//Then
Assert.AreEqual(expectedResult.Length, actualResult.Count);
for (var i = 0; i < expectedResult.Length; i++)
{
Assert.AreEqual(expectedResult[i], actualResult[i]);
}
}
public IList <int> FindLargestValues(TreeNode515 root)
{
var largestValues = new List <int>();
var buffer = new Queue <(int level, TreeNode515 node)>();
var currentLevel = 0;
buffer.Enqueue((0, root));
largestValues.Add(root.Value);
while (buffer.Count > 0)
{
var currentItem = buffer.Dequeue();
var currentNode = currentItem.node;
if (currentItem.level > currentLevel)
{
currentLevel = currentItem.level;
largestValues.Add(currentNode.Value);
}
else
{
if (currentNode.Value > largestValues[currentLevel])
{
largestValues[currentLevel] = currentNode.Value;
}
}
if (currentNode.Left != null)
{
buffer.Enqueue((currentItem.level + 1, currentNode.Left));
}
if (currentNode.Right != null)
{
buffer.Enqueue((currentItem.level + 1, currentNode.Right));
}
}
return(largestValues);
}
