从10亿个数据找出最大的N个

let arr = [];
for (let i = 0; i < 100000000; i++) {
    arr.push(Math.ceil(Math.random() * 10000000));
}

function findMax(arr, num) {
    if (arr.length <= num) {
        return arr.sort((a, b) => {
            if (a > b) {
                return 1;
            } else {
                return -1;
            }
        });
    }
    let tempMaxArr = arr.splice(0, num);
    const sortArr = function() {
        tempMaxArr = tempMaxArr.sort((a, b) => {
            if (a > b) {
                return 1;
            } else {
                return -1;
            }
        })
    }
    sortArr();
    for (let i = 0; i < arr.length; i++){
        if (arr[i] > tempMaxArr[0]) {
            // tempMaxArr.shift();
            // tempMaxArr.unshift(arr[i]);
            tempMaxArr[0] = arr[i];
            sortArr();
        }
    }
    return tempMaxArr;
}

function findBiggest(arr, num) {
    if (Object.prototype.toString.call(arr) !== '[object Array]') {
        throw new Error('请传入数字');
    }
    const diff = 100000;
    const len = Math.ceil(arr.length / diff);
    let tempTotalBigArr = [];
    for (let i = 0; i < len; i++) {
        const tempArr = arr.slice(i * diff, (i + 1) * diff);
        const tempBigArr = findMax(tempArr, num);
        tempTotalBigArr = tempTotalBigArr.concat(tempBigArr);
    }
    if (tempTotalBigArr.length > diff)  {
        findBiggest(tempTotalBigArr, num);
    } else {
        const bigArr = findMax(tempTotalBigArr, num);
        console.log(`最大的${ num }个数字：`, bigArr);
    }
}

findBiggest(arr, 100);