Determines whether there are two numbers in an ordered integer array, and the sum equals the given arbitrary integer

A few days ago in a C + + interview, the interviewer asked such a question, then the first answer is 1.

1. Iterates through the elements in the array, and the two-number addition is compared to the given integer, which is available when the number of arrays and the number of integers are small.
2. The sum of two is equal to any integer, there must be a number less than or equal to any integer 1/2, another number greater than or equal to any integer 1/2, then only need to judge the integer half, because the array is sorted, can be found by binary method
3. Directly traverse the array of elements less than or equal to any integer, by binary lookup, in the array of ordered elements in the discontinuous, compared to Method 2 save a lot of operations

Determines whether there are two numbers in an ordered integer array, and the sum equals the given arbitrary integer