Since the Sublime text 3 build 3083 update, short-cuts for building and running single file C++ programs have changed. If you loved the old shortcuts (cmd+b to compile and cmd+shift+b to run), you can restore them by adding these custom key bindings.

	{
		"keys": ["super+b"], 
		"command": "build",
		"context": [
			{ "key": "selector", "operator": "equal", "operand": "source.c++" }
		], 
		"args": {
			"build_system": "Packages/C++/C++.sublime-build",
			"variant": "Build"
		}
	},
 
	{
		"keys": ["super+shift+b"], 
		"command": "build",
		"context": [
			{ "key": "selector", "operator": "equal", "operand": "source.c++" }
		],
		"args": {
			"build_system": "Packages/C++/C++.sublime-build",
			"variant": "Run"
		}
	},

	{
		"keys": ["super+b"], 
		"command": "build",
		"context": [
			{ "key": "selector", "operator": "equal", "operand": "source.java" }
		], 
		"args": {
			"build_system": "Packages/Java/Java.sublime-build",
			"variant": "Build"
		}
	},
 
	{
		"keys": ["super+shift+b"], 
		"command": "build",
		"context": [
			{ "key": "selector", "operator": "equal", "operand": "source.java" }
		],
		"args": {
			"build_system": "Packages/Java/Java.sublime-build",
			"variant": "Run"
		}
	}

Hope this helps :)

EDIT: The previous script I mentioned had a bug : The short-cut keys were executing c++ build command even for java source code. I have resolved that bug using 'context'. 'context' helps link multiple build_systems / commands with same short-cuts. So this should do the trick. And any undefined build_systems here would be executing default behaviour for the short-cuts :)