Min Stack

Explore how to create a custom Min Stack data structure that supports pushing, popping, and retrieving the minimum value efficiently in constant time. This lesson guides you through implementing each method with optimal time complexity, helping you deepen your JavaScript skills for coding interviews focused on custom data structures.

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Statement

Design a custom stack class, Min Stack, allowing us to push, pop, and retrieve the minimum value in constant time. Implement the following methods for Min Stack:

Constructor: This initializes the Min Stack object.
Pop(): This removes and returns from the stack the value that was most recently pushed onto it.
Push(): This pushes the provided value onto the stack.
Min Number(): This returns the minimum value in the stack in $O(1)$ time.

Note: The time complexity of all the methods above should be $O(1)$ .

Constraints:

$-10^{4} \leq$ value $\leq 10^{4}$
The Pop() and Min Number() methods will always be called on non-empty stacks.
At most, $10^3$ calls will be made to Push(), Pop(), and Min Number().

Examples

JavaScript

usercode > min_stack.js

import MainStack from "./stack.js";
class MinStack {
    
    // Initializing min and main stack
    constructor() {
        // Write your code here
    }
    // Pop() removes and returns value from minStack
    pop() {
        // Write your code here
    }
    // Pushes values into minStack
    push(value) {
        // Write your code here
    }
    // Returns minimum value from MinStack in O(1) Time
    minNumber() {
        // Write your code here
    }
}
export default MinStack

Min Stack

Min Stack

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