112. Path Sum.cpp

// Definition for a binary tree node.
struct TreeNode
{
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode() : val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
};

class Solution
{
public:
    bool hasPathSum(TreeNode *root, int targetSum)
    {
        if (!root)
            return false;
        if (!root->left && !root->right)
            return root->val == targetSum;
        return hasPathSum(root->left, targetSum - root->val) || hasPathSum(root->right, targetSum - root->val);
    }
};