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PathSumII113.java
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PathSumII113.java
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/**
* Given a binary tree and a sum, find all root-to-leaf paths where each path's
* sum equals the given sum.
*
* Note: A leaf is a node with no children.
*
* Example:
*
* Given the below binary tree and sum = 22,
*
* 5
* / \
* 4 8
* / / \
* 11 13 4
* / \ / \
* 7 2 5 1
* Return:
*
* [
* [5,4,11,2],
* [5,8,4,5]
* ]
*/
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class PathSumII113 {
public List<List<Integer>> pathSum(TreeNode root, int sum) {
List<List<Integer>> res = new ArrayList<>();
pathSum(root, 0, sum, new ArrayList<>(), res);
return res;
}
private void pathSum(TreeNode root, int sumSoFar, int target, List<Integer> path, List<List<Integer>> res) {
if (root == null) return;
int newSum = sumSoFar + root.val;
path.add(root.val);
if (root.left == null && root.right == null) {
if (newSum == target) res.add(new ArrayList<>(path));
path.remove(path.size() - 1);
return;
}
pathSum(root.left, newSum, target, path, res);
pathSum(root.right, newSum, target, path, res);
path.remove(path.size() - 1);
}
}