Counter ii

81.2% acceptance

Mar 2, 2026

888

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.

Solution

TypeScript

Time O(1)

Space O(1)

LeetCode

solution.ts

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

function createCounter(init: number): Counter {
  let current = init;
  return {
  increment: () => ++current,
  decrement: () => --current,
  reset: () => {
    current = init;
    return current;
  },
  };
}

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