Hitori is a Japanese logic puzzle based on a grid of numbers. Each number is either circled or blocked. The rules are

1. Blocks cannot connect horizontally or vertically.
2. The same number cannot be circled more than once in any row or column.
3. Circles must form a single path connected horizontally and vertically, but not diagonally.

1. When a block is found, surround it with circles horizontally and vertically.
2. When a number is circled, mark all duplicate numbers in that row and column as blocks.
3. Any cell between duplicate numbers (horizontally or vertically) is always circled.
4. No circled number or group of circled numbers can be entirely surrounded by blocks.