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class Solution {
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 public:
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  bool ans = false;
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  int sum = 0;
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  void recur(TreeNode *root, int target) {
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    if (root == NULL) return;
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    sum += root->val;
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    recur(root->left, target);
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    recur(root->right, target);
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    if (root->left == NULL && root->right == NULL &&
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        sum == target) { // !!Check only if it is a leaf node....
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      ans = true;
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      return;
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    }
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    sum -= root->val; // backtracking
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    return;
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  }
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  bool hasPathSum(TreeNode *root, int targetSum) {
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    recur(root, targetSum);
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    return ans;
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  }
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};