edited and more questions added

Updated Remove Islands.py

Updated Minimum Passes Of Matrix.py

Created Minimum Passes of Matrix.py

fixed typos in Task Assignment.py

Updated Task Assignment.py

Updated Minimum Character For Words.py

Updated Next Greater Element.py

Updated Sort Stack.py

added run time & space complexity to Mnemonic.py

Updated phone Number Mnemonics.py

Updated Cycle in Graph.py

updated Suffix Trie Construction.py

Updated Valid Starting City.py

Updated Valid Starting City.py