CP and Interview Pack: Nested Loops, Early Exit and the Bug Gallery

Alice is in a mock interview, and her FizzBuzz just ran clean. The interviewer nods and asks the second question. "Now, given a list of numbers and a target, find the first pair that sums to the target." The loop is easy to start. The hard parts are what this lesson trains: which pairs to visit, how many there are, and how to stop at the answer. Exercise 3 is that exact question, graded.