⭐️
# 題目敘述
Given an integer array arr and a mapping function fn , return a new array with a transformation applied to each element.
The returned array should be created such that returnedArray[i] = fn(arr[i], i) .
Please solve it without the built-in Array.map method.
# Example 1
Input: arr = [1,2,3], fn = function plusone(n) { return n + 1; }
Output: [2,3,4]
Explanation:
const newArray = map(arr, plusone); // [2,3,4]
The function increases each value in the array by one.
# Example 2
Input: arr = [1,2,3], fn = function plusI(n, i) { return n + i; }
Output: [1,3,5]
Explanation: The function increases each value by the index it resides in.
# Example 3
Input: arr = [10,20,30], fn = function constant() { return 42; }
Output: [42,42,42]
Explanation: The function always returns 42.
# Solution
/** | |
* @param {number[]} arr | |
* @param {Function} fn | |
* @return {number[]} | |
*/ | |
var map = function(arr, fn) { | |
return arr.map((val, idx) => val = fn(val, idx)); | |
}; |
function map(arr: number[], fn: (n: number, i: number) => number): number[] { | |
return arr.map((val: number, idx: number) => val = fn(val, idx)); | |
}; |
