CodeParkFind the shortest substring of s that holds every character of t, counting repeats. A substring is a block of characters that sit side by side in s. So if t has two as, the block needs at least two as too.
- If no block of
sholds all oft, return"". - If several blocks tie for shortest, return the leftmost one, the one that starts first.
- Upper and lower case are different characters.
tis never empty. scan be up to 100,000 characters long.
Input: s = "xaybzcab", t = "abc"
Output: "cab"
Input: s = "abca", t = "aa"
Output: "abca"Both a's are needed, so the substring must stretch from the first a to the last a.
Input: s = "abc", t = "d"
Output: ""