ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
87 lines
2.1 KiB
Markdown
87 lines
2.1 KiB
Markdown
---
|
||
id: a3f503de51cfab748ff001aa
|
||
title: 成对
|
||
challengeType: 5
|
||
videoUrl: ''
|
||
dashedName: pairwise
|
||
---
|
||
|
||
# --description--
|
||
|
||
给定一个数组`arr` ，找到其总和等于第二个参数`arg`元素对，并返回它们的索引之和。您可以使用具有相同数字元素但索引不同的多个对。每对应使用尽可能低的可用指数。一旦元素被使用，它就不能被重用来与另一个元素配对。例如， `pairwise([1, 1, 2], 3)`使用indice 0处的1而不是indice 1处的1创建一对`[2, 1]` ，因为0 + 2 <1 + 2。例如， `pairwise([7, 9, 11, 13, 15], 20)`返回`6` 。总和为20的对是`[7, 13]`和`[9, 11]` 。然后我们可以用它们的索引和值写出数组。
|
||
|
||
| **指数** | 0 | 1 | 2 | 3 | 4 |
|
||
| ------ | - | - | -- | -- | -- |
|
||
| 值 | 7 | 9 | 11 | 13 | 15 |
|
||
|
||
下面我们将采用相应的索引并添加它们。 7 + 13 = 20→指数0 + 3 = 3
|
||
9 + 11 = 20→指数1 + 2 = 3
|
||
3 + 3 = 6→返回`6`如果卡住，请记住使用[Read-Search-Ask](https://forum.freecodecamp.org/t/how-to-get-help-when-you-are-stuck-coding/19514) 。尝试配对程序。编写自己的代码。
|
||
|
||
# --hints--
|
||
|
||
`pairwise([1, 4, 2, 3, 0, 5], 7)`应该返回11。
|
||
|
||
```js
|
||
assert.deepEqual(pairwise([1, 4, 2, 3, 0, 5], 7), 11);
|
||
```
|
||
|
||
`pairwise([1, 3, 2, 4], 4)`应该返回1。
|
||
|
||
```js
|
||
assert.deepEqual(pairwise([1, 3, 2, 4], 4), 1);
|
||
```
|
||
|
||
`pairwise([1, 1, 1], 2)`应该返回1。
|
||
|
||
```js
|
||
assert.deepEqual(pairwise([1, 1, 1], 2), 1);
|
||
```
|
||
|
||
`pairwise([0, 0, 0, 0, 1, 1], 1)`应返回10。
|
||
|
||
```js
|
||
assert.deepEqual(pairwise([0, 0, 0, 0, 1, 1], 1), 10);
|
||
```
|
||
|
||
`pairwise([], 100)`应该返回0。
|
||
|
||
```js
|
||
assert.deepEqual(pairwise([], 100), 0);
|
||
```
|
||
|
||
# --seed--
|
||
|
||
## --seed-contents--
|
||
|
||
```js
|
||
function pairwise(arr, arg) {
|
||
return arg;
|
||
}
|
||
|
||
pairwise([1,4,2,3,0,5], 7);
|
||
```
|
||
|
||
# --solutions--
|
||
|
||
```js
|
||
function pairwise(arr, arg) {
|
||
var sum = 0;
|
||
arr.forEach(function(e, i, a) {
|
||
if (e != null) {
|
||
var diff = arg-e;
|
||
a[i] = null;
|
||
var dix = a.indexOf(diff);
|
||
if (dix !== -1) {
|
||
sum += dix;
|
||
sum += i;
|
||
a[dix] = null;
|
||
}
|
||
}
|
||
});
|
||
return sum;
|
||
}
|
||
|
||
pairwise([1,4,2,3,0,5], 7);
|
||
```
|