一、手写算法

https://leetcode-cn.com/problems/max-chunks-to-make-sorted-ii/

思路

  • 每一个分块和排序后的数组中对应的分块数字是一样的，只是排序不同。

    代码

    1. /**
    2. * @param {number[]} arr
    3. * @return {number}
    4. */
    5. var maxChunksToSorted = function(arr) {
    6.   const sorted = [...arr];
    7.   sorted.sort((a, b) => a - b);
    9.   let count = 0,
    10.       sum1 = 0,
    11.       sum2 = 0;
    13.   for (let i = 0; i < arr.length; i++) {
    14.       sum1 += arr[i];
    15.       sum2 += sorted[i];
    17.       if (sum1 === sum2) {
    18.           count++;
    19.       }
    20.   }
    21.   return count;
    22. };

    复杂度分析

  • 时间复杂度：

  • 空间复杂度：

二、编程题

  1. // 手写题：https://bigfrontend.dev/zh/problem/implement-your-own-URLSearchParams
  1.  class MyURLSearchParams {
  2.    /**
  3.     * @params {string} init
  4.     */
  5.    constructor(init) {
  6.       this.initParams = init.split('?')[init.split('?').length-1];
  7.       this.params = []
  8.       this.initParams.split('&').forEach((item,index)=>{
  9.         const [key,value] = item.split('=');
  10.         this.params[index] = {name:key,value};
  11.       })
  12.    }
  14.    /** 
  15.     * @params {string} name
  16.     * @params {any} value
  17.     */
  18.     append(name, value) {
  19.       var val = value === undefined ? 'undefined' : value === NaN ? 'NaN' :  value.toString()
  20.       return this.params[this.params.length] = {name:name,value:val}
  21.     }
  23.    /**
  24.     * @params {string} name
  25.     */
  26.    delete(name) {
  27.      return this.params = this.params.filter((item)=>{
  28.        if(name !== item.name){
  29.          return item.value
  30.        }
  31.      })
  32.    }
  34.    /**
  35.     * @returns {Iterator} 
  36.     */
  37.   entries() {
  38.       var items = [];
  39.       this.params.forEach(function(item) { 
  40.         items.push([item.name, item.value]); 
  41.       });
  43.       var iterator = {
  44.         next: function() {
  45.           var value = items.shift();
  46.           return {done: value === undefined, value: value};
  47.         }
  48.       };
  50.       if (Symbol.iterator) {
  51.         iterator[Symbol.iterator] = function() {
  52.           return iterator;
  53.         };
  54.       }
  56.       return iterator;
  57.     };
  58.      makeIterator() {
  59.         let nextIndex = 0;
  60.         let that = this;
  61.         return {
  62.            next: function () {
  63.                return nextIndex < that.params.length 
  64.                  ? { value:[that.params[nextIndex++].name,that.params[nextIndex++].value],
  65.                    done: false
  66.                } : {
  67.                    done: true
  68.                };
  69.            }
  70.         };
  71.     }
  73.    /**
  74.     * @param {(value, key) => void} callback
  75.     */
  76.    forEach(callback) {
  77.      for(var i = 0; i<= this.params.length - 1; i++){
  78.         callback(this.params[i].value,this.params[i].name)
  79.      }
  80.    }
  82.    /**
  83.     * @param {string} name
  84.     * returns the first value of the name
  85.     */
  86.    get(name) {
  87.      return this.getAll(name).length > 0 ?this.getAll(name)[0] :null
  88.    }
  90.    /**
  91.     * @param {string} name
  92.     * @return {string[]}
  93.     * returns the value list of the name
  94.     */
  95.    getAll(name) {
  96.       var all = this.params.filter((item)=>{
  97.        if(name.split('?')[name.split('?').length - 1] === item.name){
  98.          return item.value
  99.        }
  100.      })
  101.      return all.map((item) => {return item.value})
  102.    }
  104.    /**
  105.     * @params {string} name
  106.     * @return {boolean}
  107.     */
  108.    has(name) {
  109.      var flag = false;
  110.      for(var i = 0; i<= this.params.length - 1; i++){
  111.         if(name === this.params[i].name){
  112.           flag = true;
  113.          return flag;
  114.        }
  115.      }
  116.      return flag;
  117.    }
  119.    /**
  120.     * @return {Iterator}
  121.     */
  122.    keys() {
  123.      return this.params.map((item) => {return item.name})
  124.    }
  126.    /**
  127.     * @param {string} name
  128.     * @param {any} value
  129.     */
  130.    set(name, value) {
  131.      if(this.has(name)){
  132.         this.params.forEach((item,index)=>{
  133.        if(name === item.name){
  134.          console.log(value instanceof Object)
  135.          if(value instanceof Object){
  136.           this.params[index] = {name,value:value.toString()}
  137.          }else{
  138.           this.params[index] = {name,value:value.toString()}
  139.          }
  140.        }
  141.      })
  142.      }else{
  143.          this.append(name,value)
  144.        }
  146.      console.log('this.params',this.params)
  147.    }
  149.    // sor all key/value pairs based on the keys
  150.    sort() {
  151.      this.params = this.params.sort((a, b) => a.name < b.name ? -1 : a.name > b.name ? 1 : 0);
  152.      console.log(this.params)
  153.    }
  155.    /**
  156.     * @return {string}
  157.     */
  158.    toString() {
  159.      var str = ''
  160.      this.params.forEach((item)=>{
  161.        str = str + `${item.name}=${item.value}&`;
  162.      })
  163.      return str.substring(0,str.length-1);
  164.    }
  166.    /**
  167.     * @return {Iterator} values
  168.     */
  169.    values() {
  170.      return this.params.map((item) => {return item.value})
  171.    }
  172.  }