leetcode-go/medium/609.find-duplicate-file-in-system.java

class Solution {
    public List<List<String>> findDuplicate(String[] paths) {
        List<List<String>> res = new LinkedList<>();
        HashMap<String, Integer> map = new HashMap<>();
        for (String path : paths) {
            String[] part = path.split(" ");
            for (int i = 1; i < part.length; i++) {
                String[] file = part[i].split("\\(");
                Integer idx = map.get(file[1]);
                if (idx == null) {
                    res.add(new LinkedList<String>());
                    idx = res.size() - 1;
                    map.put(file[1], idx);
                }
                String fullPath = part[0] + "/" + file[0];
                res.get(idx).add(fullPath);
            }
        }
        Iterator<List<String>> iter = res.iterator();
        while (iter.hasNext()) {
            List<String> list = iter.next();
            if (list.size() == 1) iter.remove();
        }
        return res;
    }
}