优化代码 arrayNewRepeat(array1, array2) { let result = [] for (let i = 0; i < array2.length; i++) { let obj = array2[i] let num = obj.ParticipantID let isExist = false for (let j = 0; j < array1.length; j++) { let aj = array1[j] let n = aj.id if (n == num) { isExist = true break } } if (!isExist) { result.push(obj) } } return result },
时间: 2024-02-14 11:15:13 浏览: 31
这个函数的作用是从array2中过滤掉在array1中已经存在的元素,返回过滤后的结果数组result。这个函数使用了两个for循环,时间复杂度为O(n^2)。可以考虑使用map或set等数据结构来提高查找效率,从而优化这个函数的时间复杂度。
以下是优化后的代码:
```
function arrayNewRepeat(array1, array2) {
let map = new Map();
let result = [];
for (let i = 0; i < array1.length; i++) {
let obj = array1[i];
map.set(obj.id, obj);
}
for (let i = 0; i < array2.length; i++) {
let obj = array2[i];
if (!map.has(obj.ParticipantID)) {
result.push(obj);
}
}
return result;
}
```
这个函数使用了一个map来存储array1中的元素,然后在遍历array2时,使用has方法来判断元素是否存在于map中,从而提高了查找效率,时间复杂度为O(n)。
相关问题
请优化下面的代码:function isAllDataEmpty(dataList) { let result = true; if (dataList && dataList.length > 0) { loop: for (let i = 0; i < dataList[0].data.codeData.length; i++) { let item = dataList[0].data.codeData[i]; if (i > 0) { for (let j = 0; j < item.length; j++) { if (j > 1) { let xItem = item[j]; if (xItem) { result = false; break loop; } } } } } } return result; }
&& dataList.length > 0) { for (let i = 0; i < dataList.length; i++) { if (dataList[i] && dataList[i].length > 0) { result = false; break; } } } return result; }
我可以尝试优化一下:
function isAllDataEmpty(dataList) {
if (!Array.isArray(dataList) || dataList.length === 0) {
return true;
}
return dataList.every(item => !item || item.length === 0);
}
totalsum.push(sum2, this.state.totalsum) for (let i = 0; i < totalsum.length; i++) { sum += totalsum[i] }
This code snippet has a few issues that need to be resolved.
First, the `push` method is being called with two arguments, `sum2` and `this.state.totalsum`. This will add both values as separate elements to the end of the `totalsum` array. If you want to concatenate these arrays, you can use the spread operator like this:
```
totalsum.push(...sum2, ...this.state.totalsum);
```
Second, the `for` loop has a condition that will result in an infinite loop. The loop variable `i` is never incremented or decremented, so it will always be equal to zero and the loop will never terminate. To fix this, you can add `i++` to the end of the loop body:
```
for (let i = 0; i < totalsum.length; i++) {
sum = totalsum[i];
// more code here
}
```
Finally, it's not clear what you want to do with the `sum` variable inside the loop. As it's currently written, it will just overwrite its value on each iteration, so you'll end up with the last value in the array. If you want to do something with each element of the array, you'll need to add more code inside the loop.