docs: public static void projectMap(int[] mainMap, int[] subMap,
                                    int[] newSubMap) {
  
          for (int i = 0; i < subMap.length; i++) {
              for (int j = 0; j < mainMap.length; j++) {
                  if (subMap[i] == mainMap[j]) {
                      newSubMap[i] = j;
                      break;
                  }
              }
          }
      }