Smallest Substring Of A String Containing All Characters Of Another String
1. You are given two strings s1 and s2 containing lowercase english alphabets. 2. You have to find the smallest substring of s1 that contains all the characters of s2. 3. If no such substring exists, print blank string("").
1 <= length of string s1 and s2 <= 10000
Two strings s1 and s2