知识点指南

Sorting

Sorting changes raw input order into useful order. It often makes equal values adjacent, reveals gaps, or prepares the data for a greedy decision.

什么时候使用

读题时可以留意这些信号。

Original order is not important, or positions can be stored separately.
The task asks about groups, gaps, closest/farthest values, or ordered choices.
A later scan only makes sense after arranging values.

常见错误

提交前可以检查这些小陷阱。

Sorting when original order is essential.
Sorting by the wrong key.
Comparing adjacent values before sorting.

怎么写成代码

把知识点翻译成变量、循环、判断和更新。

Read the values into an array/list.
Sort before scanning or making choices.
Compare adjacent sorted values to find gaps or groups.
Store original indices if the original position is still needed.

在 Block 题里长什么样

答题时通常会看到这些步骤被拆成代码块。

1Read N and values.
2Sort values.
3Initialise answer/group count/best gap.
4Loop through sorted neighbours.
5Update answer based on adjacent relation.
6Print result.

题目里怎么出现

读题时先找这些信号，再决定答案区应该选哪些 blocks。

The statement says order does not matter, or asks for groups by closeness.
The raw input order is described as arbitrary.
Neighbouring after sorting has a story meaning.

Count groups after sorting

一个小型模板，展示代码和 blocks 的对应关系。

C++

sort(values.begin(), values.end());
int groups = 1;
for (int i = 1; i < N; i++) {
    if (values[i] - values[i - 1] > K) groups++;
}
cout << groups << '\n';

Python

values.sort()
groups = 1
for i in range(1, N):
    if values[i] - values[i - 1] > K:
        groups += 1
print(groups)

对应 block 顺序

1Read values.
2Sort values.
3Start with one group.
4Loop through adjacent sorted values.
5Start a new group when the gap is too large.
6Output group count.