Merge pull request #2359 from Alex0M/0958-check-completeness-of-a-binary-tree

Create 0958-check-completeness-of-a-binary-tree.go

Author: Ykhan799

Diff for: go/0958-check-completeness-of-a-binary-tree.go

@@ -0,0 +1,24 @@
+func isCompleteTree(root *TreeNode) bool {
+	if root == nil {
+		return true
+	}
+
+	nilNodeFound := false
+	q := []*TreeNode{root}
+
+	for len(q) > 0 {
+		node := q[0]
+		q = q[1:]
+
+		if node == nil {
+			nilNodeFound = true
+		} else {
+			if nilNodeFound {
+				return false
+			}
+			q = append(q, node.Left)
+			q = append(q, node.Right)
+		}
+	}
+	return true
+}