_1022.java

packagecom.fishercoder.solutions.secondthousand;

importcom.fishercoder.common.classes.TreeNode;
importjava.util.ArrayList;
importjava.util.List;

publicclass_1022 {
publicstaticclassSolution1 {
publicintsumRootToLeaf(TreeNoderoot) {
List<List<Integer>> paths = newArrayList<>();
dfs(root, paths, newArrayList<>());
intsum = 0;
for (List<Integer> list : paths) {
intnum = 0;
for (inti : list) {
num = (num << 1) + i;
 }
sum += num;
 }
returnsum;
 }

privatevoiddfs(TreeNoderoot, List<List<Integer>> paths, List<Integer> path) {
path.add(root.val);
if (root.left != null) {
dfs(root.left, paths, path);
path.remove(path.size() - 1);
 }
if (root.right != null) {
dfs(root.right, paths, path);
path.remove(path.size() - 1);
 }
if (root.left == null && root.right == null) {
paths.add(newArrayList<>(path));
 }
 }
 }
}