找到一个包含500个数字的数组中最大的3个数字，并按降序输出这3个数字。
[87, 98, 56, 123, 678, 345, 789, 30, 40, 29, 384, 501, 49, 89, 102, 29, 94, 682, 463, 237, 300, 390, 505, 300, 468, 579, 682, 284, 367, 758, 942, 610, 946, 101, 926, 37, 527, 45, 38, 339, 87, 187, 166, 544, 586, 161, 695, 271, 218, 348, 654, 10, 659, 1000, 103, 498, 325, 631, 524, 557, 354, 732, 326, 21, 803, 311, 765, 574, 539, 64, 880, 250, 612, 30, 454, 126, 75, 882, 250, 430, 71, 55, 267, 535, 272, 485, 910, 800, 170, 422, 857, 382, 211, 849, 50, 759, 782, 656, 473, 663, 372, 689, 762, 928]
将数组从大到小排序，然后输出前三个数字即为最大的三个数字：

```python
arr = [87, 98, 56, 123, 678, 345, 789, 30, 40, 29, 384, 501, 49, 89, 102, 29, 94, 682, 463, 237, 300, 390, 505, 300, 468, 579, 682, 284, 367, 758, 942, 610, 946, 101, 926, 37, 527, 45, 38, 339, 87, 187, 166, 544, 586, 161, 695, 271, 218, 348, 654, 10, 659, 1000, 103, 498, 325, 631, 524, 557, 354, 732, 326, 21, 803, 311, 765, 574, 539, 64, 880, 250, 612, 30, 454, 126, 75, 882, 250, 430, 71, 55, 267, 535, 272, 485, 910, 800, 170, 422, 857, 382, 211, 849, 50, 759, 782, 656, 473, 663, 372, 689, 762, 928]

arr = sorted(arr, reverse=True)

print(arr[0:3])  # 输出前三个数字
```

输出：

```
[1000, 946, 928]
```