牛客网：NC8 二叉树中和为某一值的路径(二)

NC8 二叉树中和为某一值的路径(二)

import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;

/**
 * @author xienl
 * @description 二叉树中和为某一值的路径(二)
 * @date 2022/7/1
 */

public class Solution {
    public static void main(String[] args) {
        Solution solution = new Solution();
        TreeNode treeNode = new TreeNode(10, new TreeNode(5, new TreeNode(4), new TreeNode(7)), new TreeNode(12));
        System.out.println(solution.FindPath(treeNode, 22).toString());
    }

    ArrayList<ArrayList<Integer>> res = new ArrayList<>();
    public ArrayList<ArrayList<Integer>> FindPath(TreeNode root, int expectNumber) {
        calculation(root, expectNumber, new LinkedList<>());
        return res;
    }

    private void calculation(TreeNode node, int sum, LinkedList<Integer> list){
        if (node == null){
            return;
        }
        list.add(node.val);
        sum -= node.val;
        if (sum == 0 && node.left == null && node.right == null){
            res.add(new ArrayList<>(list));
        }
        calculation(node.left, sum , list);
        calculation(node.right, sum, list);
        list.removeLast();
    }


}

class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

    public TreeNode(int val, TreeNode left, TreeNode right) {
        this.val = val;
        this.left = left;
        this.right = right;
    }
}