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我想了解基本上打印二叉树路径的下列递归代码的功能。递归期间的字符串参数
//Node has int val; Node left; Node right;
public List<String> printPaths(Node root) {
List<String> paths = new ArrayList<String>();
printPaths(root, paths, Integer.toString(root.val)); //root is not null
return paths;
}
public void printPaths(Node root, List<String> paths, String onePath) {
if(root.left == null && root.right == null) {
paths.add(onePath);
}
if (root.left != null) {
printPaths(root.left, paths, onePath + Integer.toString(root.left.val));
}
if (root.right != null) {
printPaths(root.left, paths, onePath + Integer.toString(root.right.val));
}
}
现在这种指纹的正确路径值,但我不明白,因为我更新onePath &不要重置它的价值如何被复位为root.val每个单独的路径? 即使在为前一个路径追加“ - >”+ val之后,onePath值如何重置为每个树路径的二叉树根值?