数组转树结构采取递归和非递归两种方式，树结构转扁平化数组采取深度优先遍历（递归和非递归两种方式）和广度优先遍历实现
let arr =[
{id:2,name:'部门B',parentId:0},
{id:3,name:'部门C',parentId:1},
{id:1,name:'部门A',parentId:2},
{id:4,name:'部门D',parentId:1},
{id:5,name:'部门E',parentId:2},
{id:6,name:'部门F',parentId:3},
{id:7,name:'部门G',parentId:2},
{id:8,name:'部门H',parentId:4}
];
/**
* 数组转树 非递归求解
* 利用数组和对象相互引用 时间复杂度O(n)
* @param {Object} list
*/
function totree(list,parId) {
let obj = {};
let result = [];
//将数组中数据转为键值对结构 (这里的数组和obj会相互引用)
list.map(el => {
obj[el.id] = el;
})
for(let i=0, len = list.length; i < len; i++) {
let id = list[i].parentId;
if(id == parId) {
result.push(list[i]);
continue;
}
if(obj[id].children) {
obj[id].children.push(list[i]);
} else {
obj[id].children = [list[i]];
}
}
return result;
}
let res1 = totree(arr,0)
/**
* 数组转树 递归求解
*/
function toTree(list,parId){
let len = list.length
function loop(parId){
let res = [];
for(let i = 0; i < len; i++){
let item = list[i]
if(item.parentId === parId){
item.children = loop(item.id)
res.push(item)
}
}
return res
}
return loop(parId)
}
let result = toTree(arr,0)
/**
* 树转数组扁平化结构
* 深度优先遍历 堆栈 后进先出
*/
function deep(node){
let stack = node,
data = [];
while(stack.length != 0){
let pop = stack.pop();
data.push({
id: pop.id,
name: pop.name,
parentId: pop.parentId
})
let children = pop.children
if(children){
for(let i = children.length-1; i >=0; i--){
stack.push(children[i])
}
}
}
return data
}
//console.log(deep(res1))
/**
* 树转数组扁平化结构
* 深度优先遍历 递归
*/
function deepTraversal(data) {
const result = [];
data.forEach(item => {
const loop = data => {
result.push({
id: data.id,
name: data.name,
parentId: data.parentId
});
let child = data.children
if(child){
for(let i = 0; i < child.length; i++){
loop(child[i])
}
}
}
loop(item);
})
return result;
}
//console.log(deepTraversal(res1))
/**
* 广度优先
* 队列 先进先出
*/
function wideTraversal(node){
let stack = node,
data = [];
while(stack.length != 0){
let shift = stack.shift();
data.push({
id: shift.id,
name: shift.name,
parentId: shift.parentId
})
let children = shift.children
if(children){
for(let i = 0; i < children.length; i++){
stack.push(children[i])
}
}
}
return data
}
//console.log(wideTraversal(res1))
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版权声明：本文为CSDN博主「灿尔哈擦苏」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/susuzhe123/java/article/details/95353403
