LeetCode——226. Flip binary tree (BFS)

Title Description

Their thinking

BFS Is the core to solve this problem ,BFS The initial node of is a root node .

1. First, put the root node into the array .
2. Get the first element in the array , Then swap the left and right nodes of this element .
3. If the left node exists , Add the left node to the array .
4. If the right node exists , Then add the right node to the array .

AC Code

var invertTree = function(root) {
    
  //  Use BFS Solve the problem of flipping binary tree 
  if (!root) return null;
  const res = [root];

  while (res.length) {
    
    let cur = res.shift();
    //  Switch left and right nodes 
    [cur.left, cur.right] = [cur.right, cur.left];
    if (cur.left) {
    
      res.push(cur.left);
    }
    if (cur.right) {
    
      res.push(cur.right);
    }
  }
  return root;
};

reflection

Binary tree mirroring and reversing binary tree is a topic , On the whole, through BFS It can solve this problem efficiently .