【7 kyu】Sum of two lowest positive integers

原題目

Create a function that returns the sum of the two lowest positive numbers given an array of minimum 4 integers. No floats or empty arrays will be passed.

For example, when an array is passed like [19,5,42,2,77], the output should be 7.

[10,343445353,3453445,3453545353453] should return 3453455.

Hint: Do not modify the original array.

題目：有一個很多於四個元素的數組，計算其中兩個最小值的和。

思路：找出兩個最小的元素，而後求和

My Solution

function sumTwoSmallestNumbers(numbers) {  
    var arr = numbers.sort(function(x, y) {
        return x - y;
    });
    return arr[0] + arr[1];
};

雖然，上面的方法經過了系統的測試，可是原始數組卻被改變了！！！

MDN - Array.prototype.sort()
The sort() method sorts the elements of an array in place and returns the array.

function sumTwoSmallestNumbers(numbers) {  
  var minNums = [numbers[0], numbers[1]].sort(function(x, y) {return x-y});
  var len = numbers.length;
  for(i=2; i<len; i++){
    var num = numbers[i];
    if(num < minNums[0]) {
      minNums = [num, minNums[0]];
    } else if(num < minNums[1]){
      minNums[1] = num;
    }
  }
  return minNums[0] + minNums[1];
};

Clever Solution

function sumTwoSmallestNumbers(numbers) {  
  var [ a, b ] = numbers.sort((a, b) => a - b)
  return a + b
}

? 被標註「clever」對多的答案也用了sort， 也改變了原數組。

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對比

我寫的方法比較常規，clever solution中採用了ES6的解構賦值和箭頭函數