Given a string, sort it in decreasing order based on the frequency of characters. 'e' appears twice while 'r' and 't' both appear once. So 'e' must appear before both 'r' and 't'. Therefore "eetr" is ...

Java Collections sort api is probably most frequently used api by most developers but how many of us know which algorithms it uses behind the scenes. Lets find out. In JDK-8 (x64). For Arrays.sort ...