Amazon Software Development Engineer (SDE) Intern interview questions

The interview was concise and straight to the point. Although the question was from a topic in programming I wasn't as proficient in (graphs), I understood the concept of the first question and came up with a solution, not the most efficient but at least it worked. The follow-up question however, was a tad more difficult for me and I could not come up with a (satisfactory) solution. The interviewer fortunately was patient with me.