BFS和DFS

DFS算法和BFS算法
BFS

递归实现dfs
简单的二叉树dfs
https://leetcode-cn.com/problems/binary-tree-preorder-traversal/

var preorderTraversal = function (root) {
  let res = [];
  if (!root) {
    res = [];
  } else {
    const dfs = function (node) {
      // console.log(node);
      if (!node) return;
      res.push(node.val);
      dfs(node.left);
      dfs(node.right);
    };

    dfs(root);
  }
  return res;
};
console.log(preorderTraversal([1, null, 2, 3]));

赏

谢谢你请我吃糖果，但是还是不要了，我牙疼