LeetCode Path Sum

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool hasPathSum(TreeNode *root, int sum) {
        return dfs(root, 0, sum);
    }
    
    bool dfs(TreeNode* root, int cur_sum, int target) {
        if (root == NULL) return false;
        cur_sum = cur_sum + root->val;
        if (cur_sum == target && root->left == NULL && root->right == NULL) return true;
        if (dfs(root->left, cur_sum, target)) return true;
        if (dfs(root->right, cur_sum, target)) return true;
        return false;
    }
};

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