Write two_sum(nums, target) that returns the indexes [i, j] (i < j) of the first pair (smallest j, then smallest i) adding up to target, or [] if none.
two_sum([2, 7, 11, 15], 9) → [0, 1]
two_sum([1, 2, 3], 7) → []
Submit runs 5 tests, including hidden edge cases.
Run your code to see the output here.