DIY: Minimum Window Subsequence

Solve the interview question "Minimum Window Subsequence" in this lesson.

Problem statement

Given strings S and T, find the minimum (contiguous) substring W of S, so that T is a subsequence of W.

If there is no window in S that covers all characters in T, return an empty string "". If there are multiple minimum-length windows, return the one with the left-most starting index.


The input will be two strings S and T. The following is an example input:

S = "abcdebdde"
T = "bde"


For the above input, the output will be:


The strings "bcde" and "bdde" are both minimum subsequences, but "bcde" occurs before "bdde".

Coding exercise

For this coding exercise, you need to implement the min_window(S, T) function, where S and T are the provided strings. The function should return the minimum subsequence of T that exists in S.

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