[LeetCode] Path Sum II

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Total Accepted: 10147 Total Submissions: 37132

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

For 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 binary tree * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public ArrayList<ArrayList<Integer>> pathSum(TreeNode root, int sum) {        ArrayList<ArrayList<Integer>>   list = new ArrayList<ArrayList<Integer>>();        ArrayList<Integer>              path = new ArrayList<Integer>();                traverse(list, path, root, 0, sum);                return list;    }        public void traverse(ArrayList<ArrayList<Integer>> list, ArrayList<Integer> path, TreeNode root, int sum, int target) {        if (root == null) return;                path.add(root.val);        sum += root.val;                if (sum == target && root.left == null && root.right == null) list.add(new ArrayList<Integer>(path));                traverse(list, path, root.left, sum, target);        traverse(list, path, root.right, sum, target);                path.remove(path.size() - 1);    }}

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