第二十八题：实现数组的并、交、差、补集这四个方法 about daily HOT 2 OPEN

// 交集： 
let InterSection = function (arr1, arr2) {
    return arr1.filter((v) => arr2.indexOf(v) > -1);
}

// 并集： 
let Union = function (arr1, arr2) {
    return arr1.concat(arr2.filter((v) => !(arr1.indexOf(v) > -1)));
}

// 补集：
let Complement = function (arr1, arr2) {
    let all
    return arr1.filter((v) => !(arr2.indexOf(v) > -1));
}

// 差集:
let DifferenceSet = function (arr1, arr2) {
    return arr1.filter((v) => arr2.indexOf(v) == -1);
}

// console.log(InterSection([1,2,3,4,5], [3,4,6,7]));
// console.log(Union([1,2,3,4,5], [3,4,6,7]));
// console.log(Complement([1,2,3,4,5], [3,4,6,7]));
// console.log(DifferenceSet([1,2,3,4,5], [3,4,6,7]));