2665. Counter II

tags: leetcode 30 days js challenge Easy

2665. Counter II

題目描述

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.

範例

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

解答

TypeScript

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

function createCounter(init: number): ReturnObj {
  let count = init;
  const increment = () => ++count;
  const decrement = () => --count;
  const reset = () => (count = init);

  return {
    increment,
    decrement,
    reset,
  };
}

SheepSun, May 7, 2023

Reference

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