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| class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) {
val = x;
}
}
class Solution {
private final List<List<Integer>> res = new LinkedList<>();
public List<String> binaryTreePaths(TreeNode root) {
if (root == null) {
return new LinkedList<>();
}
List<Integer> tmp = new LinkedList<>();
res.add(tmp);
dfs(root, tmp);
return generatePath();
}
private List<String> generatePath() {
List<String> ans = new LinkedList<>();
for (List<Integer> path : res) {
StringBuilder s = new StringBuilder();
for (var n : path) {
s.append("->").append(n);
}
ans.add(s.substring(2));
}
return ans;
}
private void dfs(TreeNode root, List<Integer> tmp) {
if (root == null) {
return;
}
tmp.add(root.val);
if (root.left != null && root.right != null) {
List<Integer> tmp2 = new LinkedList<>(tmp);
res.add(tmp2);
dfs(root.left, tmp);
dfs(root.right, tmp2);
} else if (root.left != null) {
dfs(root.left, tmp);
} else if (root.right != null) {
dfs(root.right, tmp);
}
}
}
|
