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🔥Minimum Window Substring: Frequency Constrained WindowHard
SUPER HARD PROBLEM OF THE DAY+150 XP • FAANG OA TIER

High-difficulty challenge matching authentic Google, Amazon & Uber L5 online assessment conditions.

HardSliding Window•Acceptance: 42.8%

Minimum Window Substring: Frequency Constrained Window

Targeted in FAANG & Tech OA:GoogleAmazonMicrosoft
Real-World Engineering Context
Used in streaming network packet sniffers (Wireshark) and security SIEM log parsers (Splunk) to detect intrusion exploit signatures within payload streams.
Given two strings `s` and `t` of lengths `m` and `n` respectively, 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 substring, return the empty string `""`. The testcases will be generated such that the answer is unique.

Sample Test Cases

Input: ["ADOBECODEBANC","ABC"]
Expected: "BANC"
Input: ["a","a"]
Expected: "a"
Input: ["a","aa"]
Expected: ""

Constraints

  • m == s.length
  • n == t.length
  • 1 <= m, n <= 10^5
  • s and t consist of uppercase and lowercase English letters.
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