With a WBJEE GMR rank of 81,823 and ST category rank of 662, getting admission to government colleges, especially for popular branches like CSE or ECE, is very unlikely because government colleges usually close ST category seats much earlier, often within a few thousand ranks. However, you might explore option in branches with higher cutoff ranks like Civil or Mechanical in some government colleges, but chances even there are low with that rank. Private colleges might offer better opportunities for your rank. So, getting a government college seat is quite tough with these ranks.