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class Solution {
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  public boolean hasPathSum(TreeNode root, int targetSum) {
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    if (root == null) return false;
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    if (root.left == null && root.right == null) return root.val == targetSum;
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    return hasPathSum(root.right, targetSum - root.val)
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        || hasPathSum(root.left, targetSum - root.val);
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  }
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}