Given a string s and an integer k, return the length of the longest substring that contains k distinct characters.
Example 1:
<div>
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: s = "eceba", k = 2
Output: 3
Explanation: "ece" which its length is 3.</pre>
<div>
Example 2:
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: s = "aa", k = 1
Output: 2
Explanation: "aa" which its length is 2.
</pre>
</div>
</div>

K Distinct Characters

Given a string, return the size of the longest substring such that it contains at most 2 distinct characters.
Example 1:
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: "eceba"
Output: 3
Explanation: t is "ece" which its size is 3.
</pre>
Example 2:
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: "ccaabbb"
Output: 5
Explanation: t is "aabbb" which its size is 5.
</pre>

Two Distinct Character Substring

You are given a string, s. Find the length of the longest substring without repeating characters.
Example 1:
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: "abcabc"
Output: 3 
Explanation: Longest substring is <code>"abc"</code>, with the length of 3.</pre>
Example 2:
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: "ffewef"
Output: 3
Explanation: Longest substring is <code>"few"</code>, with the length of 3.</pre>
&nbsp;

Maximum Substring With Non Repeating Characters

Given 2 strings S and T, return the minimum contiguous substring W of S such that T is also a subsequence (non-contiguous) of W.&nbsp;
If there are multiple results, return the substring with the leftmost starting index. If there are no results then return an empty string.
Example 1:
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: 
S = "abcdebdde", T = "bde"
Output: "bcde"
Explanation: 
"bcde" is the answer since it occurs before "bdde" even though both substrings contains T as a subsequence and has the shortest length.
"deb" is not an answer because T is not a subsequence since the order isn't the same.
</pre>
&nbsp;

Smallest Substring Subsequence

Given 2 strings called: S and T, return the minimum substring in S that contains all characters of T. Do it in O(n) complexity. If no substring exists then return the empty string. If the substring exists then you are guaranteed to only have one unique solution.
Example:
<pre style="white-space: pre-wrap; word-break: keep-all;">Input: S = "ADOBECODEBANC", T = "ABC"
Output: "BANC"
</pre>
&nbsp;

Minimum Full Window

You are given an array nums. There is a sliding window of size k which is moving from left to right by one position each time and you can only see k numbers in the window. Return an array of maximum elements in the sliding window as it moves by one position.

Example:

<pre style="white-space: pre-wrap; word-break: keep-all;">
Input: nums = <code>[1,3,-1,-3,5,3,6,7]</code>, and k = 3
Output: <code>[3,3,5,5,6,7] 
Explanation: 
</code>
Window position Max
--------------- -----
[1 3 -1] -3 5 3 6 7 3
 1 [3 -1 -3] 5 3 6 7 3
 1 3 [-1 -3 5] 3 6 7 5
 1 3 -1 [-3 5 3] 6 7 5
 1 3 -1 -3 [5 3 6] 7 6
 1 3 -1 -3 5 [3 6 7] 7
</pre>

Note: 
You may assume k is always valid, 1 &le; k &le; input array&#39;s size for non-empty array.

Follow up: 
Could you solve it O(n)?

Problem Title	Difficulty	Frequency in Interviews
Maximum Substring With Non Repeating Characters	Medium
Minimum Full Window	Hard
Max Sliding Window	Hard
K Distinct Characters	Hard
Smallest Substring Subsequence	Hard
Two Distinct Character Substring	Hard

Most Frequently Asked Sliding Window Interview Questions

Sort By: Company Questions

Sort By: Problem Type