binary_tree_level_order_traversal

Author: hitzzc

README.md

@@ -88,6 +88,7 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [98. validate binary search tree](https://github.com/hitzzc/go-leetcode/tree/master/validate_binary_search_tree)
 #### [100. same tree](https://github.com/hitzzc/go-leetcode/tree/master/same_tree)
 #### [101. symmetric tree](https://github.com/hitzzc/go-leetcode/tree/master/symmetric_tree)
+#### [102. Binary Tree Level Order Traversal](https://github.com/hitzzc/go-leetcode/tree/master/binary_tree_level_order_traversal)
 
 
 

binary_tree_level_order_traversal/binary_tree_level_order_traversal.go

@@ -0,0 +1,31 @@
+package binary_tree_level_order_traversal
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func levelOrder(root *TreeNode) [][]int {
+	if root == nil {
+		return [][]int{}
+	}
+	stack := []*TreeNode{root}
+	rets := [][]int{}
+	for len(stack) != 0 {
+		tmpStack := []*TreeNode{}
+		ret := []int{}
+		for i := range stack {
+			ret = append(ret, stack[i].Val)
+			if stack[i].Left != nil {
+				tmpStack = append(tmpStack, stack[i].Left)
+			}
+			if stack[i].Right != nil {
+				tmpStack = append(tmpStack, stack[i].Right)
+			}
+		}
+		rets = append(rets, ret)
+		stack = tmpStack
+	}
+	return rets
+}