There is a test task, I got a little hooked on algorithms, can you tell me which one is better suited for the task?

Question

Java

There is an array of numbers from 1 to 100000000000. The array is sorted(1,2,3 ....99999999999,100000000000 ), but one digit is doubled in it(For example, [1,2,3,4,4,6,7 .. .]). It is necessary to write a method that will find the missing number in the minimum time.