37. Minimum Window Substring

You're building a search feature that needs to find the minimum window in a string containing all characters from another string. This is useful for substring matching and search optimization.

Given two strings s and t, return the minimum window substring of s such that every character in t (including duplicates) is included in the window. If there is no such window, return the empty string "".

Examples

minWindow("ADOBECODEBANC", "ABC"); // "BANC"
// Minimum window containing A, B, and C

minWindow("a", "a"); // "a"
minWindow("a", "aa"); // ""