Smallest Window with All Distinct Characters

Given a string s, find the length of the smallest contiguous substring (window) that contains all the distinct characters present in s. In other words, if we denote by \(D\) the set of distinct characters in s, you need to find the minimum length of a substring such that every character in \(D\) appears at least once in that substring.

Example:

• If s = "aabcbcdbca", the smallest window that contains all distinct characters is "dbca" and its length is 4.
• If s = "aaab", the answer is 2.

The challenge is to efficiently determine this minimum window length. A common approach uses a sliding window technique along with a frequency count to keep track of the characters within the window.

inputFormat

The input consists of a single line containing the string s (with no spaces) for which the smallest window length is to be found.

You can assume that s is non-empty.

outputFormat

Print a single integer representing the length of the smallest contiguous substring of s that contains all its distinct characters.

aabcbcdbca

4