路径综合（递归，迭代）Java

//递归法


class Solution {
    public boolean hasPathSum(TreeNode root, int targetSum) {
          if(root==null) return false;
          return find(root,targetSum-root.val);

    }public boolean find(TreeNode root,int targetSum){
        if(root.left==null&&root.right==null&&targetSum==0) return true;
            if(root.left==null&&root.right==null) return false;
            if(root.left!=null){
                targetSum-=root.left.val;
                if(find(root.left,targetSum)) return true;
                targetSum+=root.left.val;
            }
            if(root.right!=null){
                targetSum-=root.right.val;
                if(find(root.right,targetSum)) return true;
                targetSum+=root.right.val;
            }
            return false;
    }
      
}

//迭代法


class Solution {
    public boolean hasPathSum(TreeNode root, int targetSum) {
          if(root==null) return false;
          Stack stack1=new Stack<>();
          Stack satck2=new  Stack<>();
          stack1.push(root);
          satck2.push(root.val);
          while(!stack1.isEmpty()){
              int size=stack1.size();
              for(int i=0;i