LeetCode-Solutions-in-Cpp17

Solutions to high-frequency interview questions of LeetCode in C++17, taking into account both efficiency and comprehensibility.

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class Solution {
 public:
  vector<vector<int>> levelOrder(Node* root) {
    vector<vector<int>> res;
    if (!root) {
      return res;
    }
    queue<Node*> q;
    q.emplace(root);
    while (!empty(q)) {
      vector<int> line;
      int n = size(q);
      for (int i = 0; i < n; ++i) {
        Node* t = q.front();
        q.pop();
        line.emplace_back(t->val);
        for (auto& x : t->children) {
          q.emplace(x);
        }
      }
      res.emplace_back(line);
    }
    return res;
  }
};