Meta Applications Engineer Internship interview questions

I had first telephonic round today. I was not able to give efficient solution and the code which I wrote was sloppy. Call went for standard, 45 minutes. Following is the question: Given a list of ranges, find whether the target range is in the union of the given intervals. e.g: Input: a list of intervals, e.g. [-10, 10], [50, 100], [0, 20] & a target range Output: true if target can be covered by the union of all intervals e.g. return true if target is [-5, 15] return false if target is [30,60] counter-example: target is [0,100], intervals are [50,60],[20,30],[60,80],[0,20],[80,100],[30,50]