update

easy/257.binary-tree-paths.go

@@ -1,3 +1,7 @@
+import (
+	"strconv"
+)
+
 /**
  * Definition for a binary tree node.
  * type TreeNode struct {
@@ -6,6 +10,23 @@
  *     Right *TreeNode
  * }
  */
-func binaryTreePaths(root *TreeNode) []string {
-	
+func binaryTreePaths(root *TreeNode) (paths []string) {
+	if root == nil {
+		return
+	}
+	traversalPaths(root, "", &paths)
+	return
+}
+
+func traversalPaths(node *TreeNode, path string, paths *[]string) {
+	path += "->" + strconv.Itoa(node.Val)
+	if node.Left != nil {
+		traversalPaths(node.Left, path, paths)
+	}
+	if node.Right != nil {
+		traversalPaths(node.Right, path, paths)
+	}
+	if node.Left == nil && node.Right == nil {
+		*paths = append(*paths, path[2:])
+	}
 }