@LeetCode Rewind @2024

 

2665. Counter II @LeetCode

 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"

Code:

1. /**
2. * @param {integer} init
3. * @return { increment: Function, decrement: Function, reset: Function }
4. */
5. var createCounter = function(init) {
6. // let reset = init;
7. let num = init;
8. return {
9. increment: function(){
10. return ++num;
11. },
12. 
    
13. decrement: function(){
14. return --num;
15. },
16. 
    
17. reset: function(){
18. return (num = init);
19. },
20. }
21. 
    
22. };
23. 
    
24. /**
25. * const counter = createCounter(5)
26. * counter.increment(); // 6
27. * counter.reset(); // 5
28. * counter.decrement(); // 4
29. */

2704. To Be Or Not To Be @LeetCode

 Write a function expect that helps developers test their code. It should take in any value val and return an object with the following two functions.

• toBe(val) accepts another value and returns true if the two values === each other. If they are not equal, it should throw an error "Not Equal".
• notToBe(val) accepts another value and returns true if the two values !== each other. If they are equal, it should throw an error "Equal".

 

Example 1:

Input: func = () => expect(5).toBe(5)
Output: {"value": true}
Explanation: 5 === 5 so this expression returns true.

Example 2:

Input: func = () => expect(5).toBe(null)
Output: {"error": "Not Equal"}
Explanation: 5 !== null so this expression throw the error "Not Equal".

Example 3:

Input: func = () => expect(5).notToBe(null)
Output: {"value": true}
Explanation: 5 !== null so this expression returns true.

Code:

2620. Counter @LeetCode

 Given an integer n, return a counter function. This counter function initially returns n and then returns 1 more than the previous value every subsequent time it is called (n, n + 1, n + 2, etc).

 

Example 1:

Input: 
n = 10 
["call","call","call"]
Output: [10,11,12]
Explanation: 
counter() = 10 // The first time counter() is called, it returns n.
counter() = 11 // Returns 1 more than the previous time.
counter() = 12 // Returns 1 more than the previous time.

Example 2:

Input: 
n = -2
["call","call","call","call","call"]
Output: [-2,-1,0,1,2]
Explanation: counter() initially returns -2. Then increases after each sebsequent call.

 

Constraints:

• -1000 <= n <= 1000
• 0 <= calls.length <= 1000
• calls[i] === "call"

Code:

2667. Create Hello World Function @LeetCode

 Write a function createHelloWorld. It should return a new function that always returns "Hello World".

 

Example 1:

Input: args = []
Output: "Hello World"
Explanation:
const f = createHelloWorld();
f(); // "Hello World"

The function returned by createHelloWorld should always return "Hello World".

Example 2:

Input: args = [{},null,42]
Output: "Hello World"
Explanation:
const f = createHelloWorld();
f({}, null, 42); // "Hello World"

Any arguments could be passed to the function but it should still always return "Hello World".

 

Constraints:

• 0 <= args.length <= 10

Code: