Onsite
Round 1
A very obscure problem of finding a path with obstacles. It boiled down to find if a graph has connected components or not.
https://leetcode.com/tag/union-find/
or using https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/

Round 2
Warmup: Find integer frequency in a list of integers
Ordered Set for finiding an integer order in the same order using all available elements.
A combination of
https://leetcode.com/problems/minimum-window-substring/discuss/26808/Here-is-a-10-line-template-that-can-solve-most-'substring'-problems
https://leetcode.com/tag/ordered-map/

Round 3
Googlyness

Round 4
System Design
Design a bank with limited users for withdraw and transfer actions. Put exact technology choice and implementation details for each component.

Round 5
Sorting with contraints. Input set is limited and actions are constrained.

Overall, you need to finish all coding questions within the stipulated time. You will not get any cues for remaining time so its important you are extremely fast. I was just finished coding when the next interviewer arrived which did not work well in feedback. Also its required to be perfect as I realized being human making mistakes and correcting them during interview is not something Google appreciates. For system design do discuss but don't suggest suboptimal solutions as that will cut points. Be crisp, perfect and fast.