2620. Counter

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題目敘述

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.

解題思路

Solution

/**
 * @param {number} n
 * @return {Function} counter
 */
var createCounter = function(n) {
    let counter = n - 1;
    return function() {
        counter += 1;
        return counter;
    };
};

/** 
 * const counter = createCounter(10)
 * counter() // 10
 * counter() // 11
 * counter() // 12
 */

function createCounter(n: number): () => number {
    let counter = n - 1;
    return function() {
        counter += 1;
        return counter;
    }
}


/** 
 * const counter = createCounter(10)
 * counter() // 10
 * counter() // 11
 * counter() // 12
 */