LeetCode in Kotlin

2665. Counter II

Easy

Write a function createCounter. It should accept an initial integer init. It should return an object with three functions.

The three functions are:

• increment() increases the current value by 1 and then returns it.
• decrement() reduces the current value by 1 and then returns it.
• reset() sets the current value to init and then returns it.

Example 1:

Input: init = 5, calls = [“increment”,”reset”,”decrement”]

Output: [6,5,4]

Explanation:

const counter = createCounter(5); 
counter.increment(); // 6 
counter.reset(); // 5 
counter.decrement(); // 4

Example 2:

Input: init = 0, calls = [“increment”,”increment”,”decrement”,”reset”,”reset”]

Output: [1,2,1,0,0]

Explanation:

const counter = createCounter(0); 
counter.increment(); // 1 
counter.increment(); // 2 
counter.decrement(); // 1 
counter.reset(); // 0 
counter.reset(); // 0

Constraints:

• -1000 <= init <= 1000
• total calls not to exceed 1000

Solution

type ReturnObj = {
    increment: () => number
    decrement: () => number
    reset: () => number
}

function createCounter(init: number): ReturnObj {
    let n = init
    return {
        increment: () => {
            n = n + 1
            return n
        },
        decrement: () => {
            n = n - 1
            return n
        },
        reset: () => {
            n = init
            return n
        },
    }
}

/*
 * const counter = createCounter(5)
 * counter.increment(); // 6
 * counter.reset(); // 5
 * counter.decrement(); // 4
 */

export { createCounter }

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