title: When to use parent pointers in trees?
body: <p>There are many problems in which we need to find the parents or ancestors of a node in a tree repeatedly. So, in those scenarios, instead of finding the parent node at run-time, a less complicated approach seems to be using parent pointers. This is time efficient but increase space. Can anyone suggest, in which kind of problems or scenarios, it is advisable to use parent pointers in a tree?</p>
  
  <p>For example - distance between two nodes of a tree?</p>