Potential error in implementing MinStack

[jmrunkle]

Answered this one in the Java thread already:

minStack: Data Structures and Algorithm

For the record, I just reviewed the same code and came to the same conclusion: Mosh’s code is buggy. I think you need to keep track of the “min so far” in a second stack and pop off of it every time pop is called. His code fails to account for the possibility that the same value is added to the stack multiple times. For example, if I just fill the stack with the same value (say 5), it will only put one value into the minStack (5) and that will get popped the moment we pop the first 5 off of the …