SOURCE

const find = (arr,nid) =>{
  let res = '123'
  function dfs(obj){
    if (obj.id === nid){
      res = obj.name;
      return
    }
    for (let j = 0 ; j< obj.children.length ; j++){
      dfs(obj.children[j])
    }
  }
  for (let i = 0 ; i< arr.length ;i++){
    dfs(arr[i])
  }
  return res
}
var data = [
  {
    id: '100', 
    name: '上海', 
    children: [
      {
        id: '101',
        name: '浦东',
        children: [

        ]
      },
      {
        id: '102',
        name: '浦西',
        children: []
      }
    ]
  },
  {
    id: '200',
    name: '杭州',
    children: [
      {
        id: '201',
        name: '西湖区',
        children: [{
          id: '221',
          name: '蚂蚁 A 空间',
          children: []
        }]
      },
      {
        id: '202',
        name: '余杭区',
        children: []
      }
    ]
  }
];

console.log(find(data, '102'))



let s = "pwiwkew"
function utils(s){
  const nmap = new Map()
  const queue = []
  let max = 0
  for (let i = 0 ; i < s.length ; i++){
    while(nmap.has(s[i])){
      const node = queue.shift()
      nmap.delete(node)
    }
    queue.push(s[i])
    nmap.set(s[i],i)
    max = Math.max(queue.length , max)
  }
  return max
}
console.log(utils(s))