javascript算法学习打卡(第一周)

/**
 * arr 待排序数组
 * result 计算的结果数组
 */
function rangeArr(arr = [], result = []) {
  arr.forEach(item => {
    let i = /\d*$/.exec(item)[0]
    result[i] ? result[i].push(item) : (result[i] = [item])
  })
  return result.filter(Boolean)
}

/*
 * @Author: Mr Jiang.Xu
 * @Date: 2019-08-31 00:05:33
 * @Last Modified by:   Mr Jiang.Xu
 * @Last Modified time: 2019-08-31 00:05:33
 */
function cartesian(arr) {
  if (arr.length < 2) return arr[0] || [];
  return [].reduce.call(arr, function (col, set) {
    let res = [];
    col.forEach(c => {
        set.forEach(s => {
          let t = [].concat(Array.isArray(c) ? c : [c]);
          t.push(s);
          res.push(t);
        })
    });
    return res;
  });
}

// 创建集合,并实现交集,差集,补集,并集
function MySet() {
  let items = {}
  // 判断值是否存在
  this.has = function(val) {
    return val in items
  }
  // 添加
  this.add = function(val) {
    if(!this.has(val)) {
      items[val] = val
      return true
    }
    return false
  }
  // 移除
  this.remove = function(val) {
    if(this.has(val)) {
      delete items[val]
      return true
    }
    return false
  }
  // 清空
  this.clear = function() {
    items = {}
  }
  // 大小
  this.size = function() {
    return Object.keys(items).length
  }
  // 取值
  this.values = function() {
    return Object.keys(items)
  }
  // 并集
  this.union = function(otherSet) {
    let unionSet = new Set()
    let values = this.values()
    for(let i=0; i < values.length; i++) {
      unionSet.add(values[i])
    }

    values = otherSet.values()
    for(let i=0; i < values.length; i++) {
      unionSet.add(values[i])
    }

    return unionSet
  }
  // 交集
  this.intersection = function(otherSet) {
    let intersectionSet = new Set()
    let values = this.values()
    for(let i=0; i<values.length; i++) {
      if(otherSet.has(values[i])) {
        intersectionSet.add(values[i])
      }
    }
    return intersectionSet
  }
  // 差集
  this.difference = function(otherSet) {
    let differenceSet = new Set()
    let values = this.values()
    for(let i = 0; i < values.length; i++) {
      if(!otherSet.has(values[i])) {
        differenceSet.add(values[i])
      }
    }
    return differenceSet
  }
  // 子集
  this.subset = function(otherSet) {
    if(this.size() > otherSet.size()) {
      return false
    }else {
      let values = this.values()
      for(let i=0; i<values.length; i++) {
        if(!otherSet.has(values[i])) {
          return false
        }
      }
      return true
    }
  }
}