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## Playlist CSES Problem Set Solution-

playlist cses problems solution with code and explanation.
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

### Solution-

this problem can be solved in O(1) time.You should follow the following step
take input in a vector.
make two iterator i and j
check weather ith song is already played or not if not insert it into map and update max if max<currans.
If ith song  already  played remove all element till ith element form map and update currans value as currans=(i-j);.