JAVA | 100% Faster 100% Space | HashSet Solution
```\nclass Solution {\n    public String destCity(List> paths) {\n        HashSet source=new HashSet<>();\n        for(List loop : paths)\n            source.ad
```\nclass Solution {\n    public String destCity(List<List<String>> paths) {\n        HashSet<String> source=new HashSet<>();\n        for(List<String> loop : paths)\n            source.add(loop.get(0));\n        for(List<String> loop :paths)\n            if(!source.contains(loop.get(1)))\n                return loop.get(1);\n        return "";\n    }\n}
['Java']