> For the complete documentation index, see [llms.txt](https://liuyang89116.gitbook.io/my-leetcode-book/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://liuyang89116.gitbook.io/my-leetcode-book/post_chapter_3_array/problem_228_summary_ranges.md).

# Problem 228: Summary Ranges

> <https://leetcode.com/problems/summary-ranges/>

## 思路

* 着重在于判断是否到了最后一个元素

```java
public class Solution {
    public List<String> summaryRanges(int[] nums) {
        List<String> res = new ArrayList<String>();
        for (int i = 0; i < nums.length; i++) {
            int val = nums[i];
            while (i < nums.length - 1 && nums[i + 1] - nums[i] == 1) i++;
            if (val != nums[i]) {
                res.add(val + "->" + nums[i]);
            } else {
                res.add(val + "");
            }
        }

        return res;
    }
}
```

## 易错点

1. int 转 String

   ```java
   res.add(val + "");
   ```