如果数组中任意元素的和等于给定值，则检查数组

Question

[1,2,3,6], 3 = True <== 1+2=3
[1,2,3,6], 9 = True <== 3+6=9
[1,2,3,6], 5 = True <== 2+3=5
[1,2,3,6], 10 = False <== 1+2, 2+3, 3+6, 6+1 not equal to 10
[6,2,3,1], 10 = False <== 6+2, 2+3, 3+1, 1+6 not equal to 10
[6,3,3,1], 6 = True <== 3+3=6

如果给定的和等于数组中任意两个元素的和，函数需要返回true；否则函数需要返回false。

Answer 1

您可以使用函数一些来检查至少一个操作是true。

这种方法遵循您的用例

let check = (sum, arr) => arr.concat(arr[0]).some((n, i, a) => (n + a[i+1]) === sum);
    
console.log(check(3, [1,2,3,6]));
console.log(check(9, [1,2,3,6]));
console.log(check(5, [1,2,3,6]));
console.log(check(10, [1,2,3,6]));
console.log(check(10, [6,2,3,1]));
console.log(check(6, [6,3,3,1]));
console.log(check(7, [3,1,2,4]));
console.log(check(7, []));

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Answer 2

您必须遍历值数组。不熟悉javascript，以下是java函数中的代码：

public boolean checkSum(){
  int sumValue = 10; //value you want to check, could be passed in as a parameter
  int arr[4] = {1,2,4,6};
  for (int n = 0; n < arr.length; n++){
    for (int x = 0; x < arr.length; x++){
      if ( (arr[n] + arr[x] == sumValue) && (n != x) ){ //need to ensure same slot is being added
        return true;
      }
    }
  }
  return false;
}

希望这能有所帮助！

Answer 3

这里有一个非常简单的方法来检查数组中的两个数字是否等于一个值。注意，这只允许不同的和（与自身相加的数字不计算）。

function test(n, arr){
   return arr.some((item, i) => arr.slice(i+1).includes(n-item))
}

let arr = [1, 2, 3, 6]

console.log(test(5, arr))   // true 2+3
console.log(test(4, arr))   // true 1+3
console.log(test(12, arr))  // false because 6 + 6 doesn't count
console.log(test(10, arr))  // false no sums