Walmart Software Developer interview questions

1) Implement cache with proper synchronization. 2) Given heights of buildings, find the water clogged above them. when it rains.Width of all are same and placed next to each other with no space in between them. Example: heights are : 4,2.6 Water clogged will be 2 units above 2nd building. 3) Given n clusters of k machines, need to transfer one file to all of them. Find best way to do it. Working of torrent as well.