@Test
public void testMaxSubStringKUniqueChars() throws Exception {
String input = "abcbbbbcccbdddadacb";
String expectedOutput = "bcbbbbcccb";
LongestSubstring longestSubstring = new LongestSubstring();
String result = longestSubstring.maxSubStringKUniqueChars(input, 2);
assertEquals(result, expectedOutput);
}
@Test
public void testMaxSubStringKUniqueChars4() throws Exception {
String input = "aaaaaaaaaaaaaaaa";
String expectedOutput = null;
LongestSubstring longestSubstring = new LongestSubstring();
String result = longestSubstring.maxSubStringKUniqueChars(input, 2);
assertEquals(result, expectedOutput);
}