Create an array of 250 booleans. Go through the list 3 times. First all the 1 digit numbers, then the 2 and 3 digit numbers. Set the array entry for the resu

Create an array of 250 booleans. Go through the list 3 times. First all the 1 digit numbers, then the 2 and 3 digit numbers. Set the array entry for the resulting numbers to true. The entry that is false is the missing number.