Simple HashSet Solution in JAVA with explaination
The solution here is to Find such destinations which are not the source of any destination\nThe first loop there is to add all the elements in the set (In set, 
The **solution** here is to **Find such destinations which are not the source of any destination**\nThe first loop there is to add all the elements in the set (In set, we cannot have repeated values) and then we just find the `paths.get(i).get(1)` (the 2nd column string) and check it is present, If it is present, we return that. :)\n```\nclass Solution {\n    public String destCity(List<List<String>> paths) {\n        HashSet<String> sourceCity= new HashSet<String>();\n        for(int i=0;i<paths.size();i++)\n        {\n            sourceCity.add(paths.get(i).get(0));\n        }\n        for(int i=0;i<paths.size();i++)\n        {\n            if(!sourceCity.contains(paths.get(i).get(1)))\n                return paths.get(i).get(1);\n            \n        }\n        return "NO";\n    }\n}\n```
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