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removeMin

Language/Type: Java Collections Stacks and Queues
Author: Stuart Reges (on 2014/02/13)

Write a method removeMin that takes a stack of integers as a parameter and that removes and returns the smallest value from the Stack. For example, if a variable called s stores the following sequence of values: 

        bottom [2, 8, 3, 19, 7, 3, 2, 42, 9, 3, 2, 7, 12, -8, 4] top

and we make the following call: 

        int n = removeMin(s);

the method removes and returns the value -8 from the stack, so that the variable n will be -8 after the call and s will store the following values: 

        bottom [2, 8, 3, 19, 7, 3, 2, 42, 9, 3, 2, 7, 12, 4] top

If the minimum value appears more than once, all occurrences of the minimum should be removed from the stack. For example, given the ending value of the stack above, if we again call removeMin(s), the method would return 2 and would leave the stack in the following state: 

        bottom [8, 3, 19, 7, 3, 42, 9, 3, 7, 12, 4] top

You are to use one queue as auxiliary storage to solve this problem. You may not use any other auxiliary data structures to solve this problem, although you can have as many simple variables as you like. You also may not solve the problem recursively. Your solution must run in O(n) time.

Your method should throw an IllegalArgumentException if the stack is empty. In writing your method, assume that you are using the Stack and Queue interfaces and the ArrayStack and LinkedQueue implementations discussed in lecture.

Type your solution here:


This is a method problem. Write a Java method as described. Do not write a complete program or class; just the method(s) above.

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