C++二叉树找最小值方法详解

struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
};
int findMin(TreeNode* root) {
if (root == nullptr) {
// 防止空树访问错误
throw std::invalid_argument("树为空");
}
if (root->left == nullptr) {
return root->val;  // 最左节点即为最小值
}
return findMin(root->left);
}

int findMinIterative(TreeNode* root) {
    if (root == nullptr) {
        throw std::invalid_argument("树为空");
    }
    while (root->left != nullptr) {
        root = root->left;
    }
    return root->val;
}

void traverseAndCompare(TreeNode* root, int& minVal) {
    if (root == nullptr) return;
    if (root->val < minVal) minVal = root->val;
    traverseAndCompare(root->left, minVal);
    traverseAndCompare(root->right, minVal);
}
int findMinInGeneralTree(TreeNode* root) {
if (root == nullptr) {
throw std::invalid_argument("树为空");
}
int minVal = root->val;
traverseAndCompare(root, minVal);
return minVal;
}