Java program using data structures (Trees and nodes)

Solution must be in Java only. The input will contain a sequence of commands (as described below), each on a separate line containing no more than eighty characters. Item names are case sensitive, and each is no longer than ten characters. The command names (DEPEND, INSTALL, REMOVE and LIST) always appear in uppercase starting in column one, and item names are separated from the command name and each other by one or more spaces. All appropriate DEPEND commands will appear before the occurrence of any INSTALL command that uses them; there will be at most one dependency list per item. The end of the input is marked by a line containing only the word END. There will be at most 1000 lines in the input. Command : DEPEND item1 item2 [item3 ...] Meaning : item1 depends on item2 (and item3 . . . ) Command : INSTALL item1 Meaning : install item1 and those on which it depends Command : REMOVE item1 Meaning : remove item1, and those on which it depends, if possible Command : LIST Meaning : list the names of all currently-installed components in sequence of installation The output is as in the Credit level, except for the following. As in the Credit level, immediately after a circular dependency has been created through a DEPEND command, a warning should be given. In the Distinction level, there should be a second line recommending a dependency to delete. In the first instance, this should be the most recently encountered dependency statement from the largest cycle. Subsequent DEPEND commands should also be followed by the warning; however, the suggested dependency statement might change (because the cycle size has changed). As before, other remaining non-DEPEND commands after that point, however, should be echoed, but with no actions taken in response (so the echoed commands should be followed by nothing). When there are multiple longest cycles, the recommendation for dependency deletion should be based on the first encountered longest cycle. This should be repeated, but recommending the most recently encountered dependency statement from the smallest cycle. Sample input : DEPEND TELNET TCPIP NETCARD DEPEND TCPIP NETCARD DEPEND DNS TCPIP NETCARD DEPEND BROWSER TCPIP HTML INSTALL foo DEPEND BROWSER2 BROWSER3 TCPIP HTML DEPEND BROWSER3 BROWSER2 DEPEND NETCARD BROWSER INSTALL NETCARD INSTALL TELNET REMOVE NETCARD INSTALL BROWSER INSTALL DNS LIST REMOVE TELNET REMOVE NETCARD REMOVE DNS REMOVE NETCARD INSTALL NETCARD REMOVE TCPIP REMOVE BROWSER REMOVE TCPIP END Sample output : DEPEND TELNET TCPIP NETCARD DEPEND TCPIP NETCARD DEPEND DNS TCPIP NETCARD DEPEND BROWSER TCPIP HTML INSTALL foo Installing foo DEPEND BROWSER2 BROWSER3 TCPIP HTML DEPEND BROWSER3 BROWSER2 Found cycle in dependencies Suggest removing DEPEND BROWSER3 BROWSER2 DEPEND NETCARD BROWSER Found cycle in dependencies Suggest removing DEPEND NETCARD BROWSER INSTALL NETCARD INSTALL TELNET REMOVE NETCARD INSTALL BROWSER INSTALL DNS LIST REMOVE TELNET REMOVE NETCARD REMOVE DNS REMOVE NETCARD INSTALL NETCARD REMOVE TCPIP REMOVE BROWSER REMOVE TCPIP END Sample input : DEPEND TELNET TCPIP NETCARD DEPEND TCPIP NETCARD DEPEND DNS TCPIP NETCARD DEPEND BROWSER TCPIP HTML INSTALL foo DEPEND NETCARD BROWSER DEPEND BROWSER2 BROWSER3 TCPIP HTML DEPEND BROWSER3 BROWSER2 Sample output : DEPEND TELNET TCPIP NETCARD DEPEND TCPIP NETCARD DEPEND DNS TCPIP NETCARD DEPEND BROWSER TCPIP HTML INSTALL foo Installing foo DEPEND NETCARD BROWSER Found cycle in dependencies Suggest removing DEPEND NETCARD BROWSER DEPEND BROWSER2 BROWSER3 TCPIP HTML Found cycle in dependencies Suggest removing DEPEND NETCARD BROWSER DEPEND BROWSER3 BROWSER2 Found cycle in dependencies Suggest removing DEPEND NETCARD BROWSER