#include "leetcode.h" class Solution { public: int ans; int minCameraCover(TreeNode *root) { if (helper(root) == 0) ans++; return ans; } private: int helper(TreeNode *root) { if (!root) return 1; int l = helper(root->left); int r = helper(root->right); if (l == 0 || r == 0) { ans++; return 2; } else if (l == 2 || r == 2) return 1; else return 0; } }; int main() {}