added node, heap and tests classes
added tests for node
added "Add" method for heap
used int as key type
added 'merge' and 'extractMin' methods
fix style and copyPaste
fixed style and mistakes
fix style
added gradle
added extractByKey and decreaseKey methods
refactoring
refactoring
remove comments
added test and refactoring
Added Triangle lab files
Fixed folder's name
Merge remote-tracking branch 'upstream/master' into lab1-tdd-triangle
Fixing folders
Fixing folders
Added project to settings file
Add .gradle config