ajeshrkurup
9/30/2018 - 2:03 AM

Missing number in an array

FInd the missing number in an array, given n - which is the upper limit of array, array contains numbers 1 - n-1, which means one number is missing.

missingNum
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function missingNum(n, arr) {
  var sum = n*(n+1)/2;
  
  for(var i=0; i<arr.length; i++) {
    sum -= arr[i];
  }
  console.log(sum);
  return sum;
}

missingNum(5, [4,2,3,5]);