2665. Counter II

Problem Link

Description

---

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
• 0 <= calls.length <= 1000
• calls[i] is one of "increment", "decrement" and "reset"

Solution

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TypeScript

type ReturnObj = {
    increment: () => number,
    decrement: () => number,
    reset: () => number,
}
 
function createCounter(init: number): ReturnObj {
    let x = init;
 
    return {
        increment: () => ++x,
        decrement: () => --x,
        reset: () => x = init
    }
};
 
/**
 * const counter = createCounter(5)
 * counter.increment(); // 6
 * counter.reset(); // 5
 * counter.decrement(); // 4
 */