find the missing number 1- 1000

interview_question_mobileodt

// find the missing number 1- 1000


const min =0, max=1000;
let arr = new Array(max).fill(0).map((v,k)=> k);
const erase = Math.floor(Math.random() * (max - min + 1)) + min;
arr.splice(erase,1);



const findMissing = (arr) => {
    const expected_sum = new Array(max).fill(0).map((v,k)=> k).reduce((sum,i) => sum + i);
    const sum = arr.reduce((sum,i) => sum + i);

    return expected_sum - sum;
}

const res = findMissing(arr);
console.log(res == erase,res, erase);