从零开始Leetcode – Day 5
5，6，7被吞掉了。
不会广度优先搜索， Binary Tree Level Order Traversal 这题不会做。
https://leetcode.com/problems/binary-tree-level-order-traversal/
明天加油。
Binary Tree Level Order Traversal
https://leetcode.com/problems/binary-tree-level-order-traversal/1
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37/**
* @param {TreeNode} root
* @return {number[][]}
*/
var levelOrder = function(root) {
var res = [];
if(!root){
return res;
}
var queue = [];
queue.push(root);
var curNum = 0;
var lastNum = 1;
var list = [];
while(queue.length){
var cur = queue.shift();
lastNum --;
list.push(cur.val);
if(cur.left !== null){
queue.push(cur.left);
curNum++;
}
if(cur.right !== null){
queue.push(cur.right);
curNum ++;
}
if(lastNum === 0){
lastNum = curNum;
curNum = 0;
res.push(list);
list = [];
}
}
return res;
};