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Playlist CSES Problems set solution-

Playlist problem statement-
• Time limit: 1.00 s
•
• Memory limit: 512 MB
You are given a playlist of a radio station since its establishment. The playlist has a total of $n$ songs.

What is the longest sequence of successive songs where each song is unique?

Input

The first input line contains an integer $n$: the number of songs.

The next line has $n$ integers ${k}_{1},{k}_{2},\dots ,{k}_{n}$: the id number of each song.

Output

Print the length of the longest sequence of unique songs.

Constraints
• $1\le n\le 2\cdot {10}^{5}$
• $1\le {k}_{i}\le {10}^{9}$
Example

Input:
81 2 1 3 2 7 4 2

Output:5

Playlist CSES Problems set solution-

Step -1 store value in hashmap so that we can check that song played before or not.
step -2 make two-pointer i and j if v[i] has occurred earlier remove all element till v[i] and update ans.new length will be (i-j).
Step 3- if v[i]  not occurred simply update ans by one.