1233. Remove Sub-Folders from the Filesystem

 JAVA

• class Solution {
      public List<String> removeSubfolders(String[] folder) {
          Arrays.sort(folder);
          List<String> ans = new ArrayList<>();
          ans.add(folder[0]);
          for (int i = 1; i < folder.length; ++i) {
              int m = ans.get(ans.size() - 1).length();
              int n = folder[i].length();
              if (m >= n
                  || !(ans.get(ans.size() - 1).equals(folder[i].substring(0, m))
                      && folder[i].charAt(m) == '/')) {
                  ans.add(folder[i]);
              }
          }
          return ans;
      }
  }

C++

• class Solution {
  public:
      vector<string> removeSubfolders(vector<string>& folder) {
          sort(folder.begin(), folder.end());
          vector<string> ans = {folder[0]};
          for (int i = 1; i < folder.size(); ++i) {
              int m = ans.back().size();
              int n = folder[i].size();
              if (m >= n || !(ans.back() == folder[i].substr(0, m) && folder[i][m] == '/')) {
                  ans.emplace_back(folder[i]);
              }
          }
          return ans;
      }
  };