二叉树中和为某一值的路径(三)

import java.util.*;



public class Solution {
    
    public int count = 0;
    public int FindPath (TreeNode root, int sum) {
        // write code here
        if(root == null){
            return count;
        }
        
        method(root, sum);
        //从左树重新计算
        FindPath(root.left, sum);
        //从右数重新计算
        FindPath(root.right, sum);
        
        return count;
    }
    
    //求和判断是否满足sum
    public void method(TreeNode root, int sum){
        if(root == null){
            return ;
        }
        
        sum-=root.val;
        
        if(sum == 0){
            count++;
        }
        
        //计算左数
        method(root.left, sum);
        //计算右数
        method(root.right, sum);
    }
}