Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. - Node.js Data Structure

Node.js examples for Data Structure:Stack

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Description

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

Demo Code


'use strict';//from ww  w.  j a v  a 2s . c om
/* 

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

push(x) -- Push element x onto stack.
pop() -- Removes the element on top of the stack.
top() -- Get the top element.
getMin() -- Retrieve the minimum element in the stack.

*/

function MinStack() {};

MinStack.prototype = new Array;

MinStack.prototype.top = function() {
  return this[0];
}

MinStack.prototype.getMin = function() {
    if (this.length === 1) {
      return this[0];
    } else {
      var min = this[0],
        i = 1;
      for (; i < this.length; i++) {
        if (this[i] < min) {
          min = this[i];
        }
      }
      return min;
    }
}

var arr = new MinStack();
Array.prototype.push.apply(arr, [2, 1, 'a']);
arr.getMin(); // 1
arr.top(); //2

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