LeetCode 2665. Counter II TypeScript Solution | Explanation + Code

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"

Solutions

Solution 1

TypeScript

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