111. 二叉树的最小深度

为保证权益，题目请参考 111. 二叉树的最小深度(From LeetCode).

解决方案1

CPP

#include <algorithm>

using namespace std;

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:
  int minDepth(TreeNode *root) {
    if (root == nullptr) {
      return 0;
    } else {
      if (root->left == nullptr && root->right == nullptr) {
        return 1;
      } else if (root->left != nullptr && root->right == nullptr) {
        return minDepth(root->left) + 1;
      } else if (root->left == nullptr && root->right != nullptr) {
        return minDepth(root->right) + 1;
      } else if (root->left != nullptr && root->right != nullptr) {
        return min(minDepth(root->right), minDepth(root->left)) + 1;
      }
      return 0;
    }
  }
};