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0102-binary-tree-level-order-traversal.go
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0102-binary-tree-level-order-traversal.go
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func levelOrder(root *TreeNode) [][]int {
// nil check
if root == nil {
return nil
}
var result [][]int
level := 0
q := make([]*TreeNode,1)
q[0] = root
for len(q) > 0 {
curLen := len(q)
//add elements to the queue per level
for i := 0; i < curLen; i++ {
//queue implementation : delete element from front(1st element of slice)
node := q[0]
q = q[1:]
if len(result) <= level {
//create new slice with first value of the level and append to result matrix
result = append(result,[]int{node.Val})
}else {
//add values to the slice created per level
result[level] = append(result[level],node.Val)
}
//queue implementation : add element at Back( after last element of slice by append)
//add left node at queue
if node.Left != nil {
q = append(q,node.Left)
}
//add Right node at queue
if node.Right != nil{
q = append(q,node.Right)
}
}
//increment the level after adding current elements to result
level++
}
return result
}