# WPC 2017/Round 10

The namesake of this round is Parallel Universe I and Parallel Universe II by Prasanna Seshadri, held in 2014.[1]

Duration: 50 minutes. Total point value: 650 points. Round winner: Ken Endo and Kota Morinishi (both Japan), 510 points.

### Puzzles

The puzzles were called "Optimizer"s, but since each puzzle was promised to have a unique solution, they are not traditional Optimisers.

Round note: This round contains 16 puzzles across the same 16 puzzle types that appear in the Evergreens round, but with a slight tweak in the form of an optimization requirement in each puzzle. All puzzles in this round have multiple solutions but have a unique solution if the optimization requirement is met. It is part of solving to use the optimization and achieve a single solution.

 1 Four Winds Optimizer by Rohan Rao, 15 points

Optimization: Maximize the number of vertical line segments.

 Puzzle 1: Example Puzzle 1: Solution
 2 Skyscrapers Optimizer by Deb Mohanty, 90 points

Optimization: Maximize the sum of missing outside clues.

 Puzzle 2: Example Puzzle 2: Solution
 3 Masyu Optimizer by Deb Mohanty, 20 points

Optimization: Maximize the number of cells the loop visits.

 Puzzle 3: Example Puzzle 3: Solution
 4 Arrows Optimizer by Amit Sowani, 25 points

Optimization: Maximize the number of arrows which point in the given direction. (For example, right(➔).)

 Puzzle 4: Example Puzzle 4: Solution
 5 Magnets Optimizer by Prasanna Seshadri, 75 points

Optimization: Minimize the rows and columns, i.e. total directions, containing equal number of positive and negative half-plates.

 Puzzle 5: Example Puzzle 5: Solution
 6 Star Battle Optimizer by Deb Mohanty, 90 points

Optimization: Maximize the largest rectangle, in terms of area, without any stars.

 Puzzle 6: Example (1 star) Puzzle 6: Solution
 7 Akari Optimizer by Deb Mohanty, 20 points

Optimization: Maximize the number of light bulbs used.

 Puzzle 7: Example Puzzle 7: Solution
 8 Tents Optimizer by Deb Mohanty, 20 points

Optimization: Maximize the length of the longest orthogonally connected chain of tents and trees. A chain is defined as a continuous, non-overlapping, non-branching, non-backtracking path of consecutive cells containing tents or trees in each cell.

 Puzzle 8: Example Puzzle 8: Solution
 9 Mastermind Optimizer by Deb Mohanty, 20 points

Optimization: Maximize the four-digit number formed by the series.

 Puzzle 9: Example Puzzle 9: Solution
 10 Yajilin Optimizer by Ashish Kumar, 30 points

Optimization: Minimize the number of shaded cells.

 Puzzle 10: Example Puzzle 10: Solution
 11 Cave Optimizer by Deb Mohanty, 15 points

Optimization: Some clues are replaced by question marks (?). Maximize the sum of those clues.

 Puzzle 11: Example Puzzle 11: Solution
 12 Battleships Optimizer by Prasanna Seshadri, 20 points

Optimization: Some ships of the fleet will NOT appear in the grid, but only ships within the fleet can be used. Maximize the number of cells occupied by ships in the final solution.

 Puzzle 12: Example (Standard fleet of size 4) Puzzle 12: Solution
 13 Coral Optimizer by Prasanna Seshadri, 50 points

Optimization: Maximize the number of cells used by the largest un-shaded group in the grid.

 Puzzle 13: Example Puzzle 13: Solution
 14 Doppelblock Optimizer by Deb Mohanty, 30 points

Optimization: Minimize the number of white cells adjacent (sharing an edge) to shaded cells.

 Puzzle 14: Example Puzzle 14: Solution
 15 Different Neighbours Optimizer by Deb Mohanty, 55 points

Optimization: Minimize the number of 1’s placed in the grid.

 Puzzle 15: Example Puzzle 15: Solution
 16 Cross Number (Crisscross) Optimizer by Deb Mohanty, 75 points

Optimization: Some numbers are not found in the grid. Minimize the sum of those numbers.

 Puzzle 16: Example Puzzle 16: Solution