Minimum Window Substring

Find the shortest contiguous substring of text that contains every character of pattern, including repeats. If several are equally short, return the leftmost.

Implement min_window(text, pattern).

Input

text: The text to search. pattern: The characters that must appear.

Output

Return the shortest window, or an empty string if none exists.

Constraints

1 ≤ length of text, pattern ≤ 100,000 (ASCII)

Examples

Input:
text = "ADOBECODEBANC"
pattern = "ABC"

Expected output:
expected = "BANC"

Input:
std::string text = "ADOBECODEBANC";
std::string pattern = "ABC";

Expected output:
std::string expected = "BANC";

Input:
string text = "ADOBECODEBANC";
string pattern = "ABC";

Expected output:
string expected = "BANC";

Input:
text = "a"
pattern = "aa"

Expected output:
expected = ""

Input:
std::string text = "a";
std::string pattern = "aa";

Expected output:
std::string expected = "";

Input:
string text = "a";
string pattern = "aa";

Expected output:
string expected = "";

References

This challenge is adapted for CodeUtility. Follow the statement and constraints above.

• From Problems to Performance: Two Decades of Programming Contests in the CCSC Southeast