Package g0101_0200.s0155_min_stack

Class MinStack

java.lang.Object
g0101_0200.s0155_min_stack.MinStack
public class MinStack extends Object
155 - Min Stack.

Easy

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

Implement the MinStack class:

  • MinStack() initializes the stack object.
  • void push(int val) pushes the element val onto the stack.
  • void pop() removes the element on the top of the stack.
  • int top() gets the top element of the stack.
  • int getMin() retrieves the minimum element in the stack.

Example 1:

Input

 ["MinStack","push","push","push","getMin","pop","top","getMin"]
 \[\[],[-2],[0],[-3],[],[],[],[]]

Output: [null,null,null,null,-3,null,0,-2]

Explanation:

 MinStack minStack = new MinStack();
 minStack.push(-2);
 minStack.push(0);
 minStack.push(-3);
 minStack.getMin(); // return -3
 minStack.pop();
 minStack.top(); // return 0
 minStack.getMin(); // return -2

Constraints:

  • -231 <= val <= 231 - 1
  • Methods pop, top and getMin operations will always be called on non-empty stacks.
  • At most 3 * 104 calls will be made to push, pop, top, and getMin.

  • Constructor Details

    • MinStack

      public MinStack()

  • Method Details

    • push

      public void push(int val)

    • pop

      public void pop()

    • top

      public int top()

    • getMin

      public int getMin()