# Longest Substring with At Most K Distinct Characters

Given a string **S** and an integer **K**, return *the length of the longest substring of* **S** *that contains at most* **K** **distinct*** characters*.

```
public class Solution {
public int lengthOfLongestSubstringKDistinct(String S, int K) {
int[] charCount = new int[256];
char[] chS = S.toCharArray();
int distinctNum = 0, leftIndex = 0, maxLen = 0;
for (int rightIndex = 0; rightIndex < chS.length; rightIndex++) {
if (charCount[chS[rightIndex]]++ == 0) distinctNum++;
if (distinctNum > K) {
while (--charCount[chS[leftIndex++]] > 0);
distinctNum--;
}
maxLen = Math.max(maxLen, rightIndex - leftIndex + 1);
}
return maxLen;
}
}
```

## Related Problems

Given a string s, find the length of the **longest** **substring **without repeating characters.

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Return *the shortest such subarray and output its length*.

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An **Anagram** is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

You are given an array of non-overlapping intervals intervals where intervals[i] = [starti, endi] represent the start and the end of the ith interval and intervals is sorted in ascending order by starti. You are also given an interval newInterval = [start, end] that represents the start and end of another interval.

Insert newInterval into intervals such that intervals is still sorted in ascending order by starti and intervals still does not have any overlapping intervals (merge overlapping intervals if necessary).

Return intervals* after the insertion*.

**Note** that you don't need to modify intervals in-place. You can make a new array and return it.