ROUND WPF PUZZLE COMPETITION BOOKLET

ROUND 82020

WPF PUZZLE GP 2020COMPETITION BOOKLET

Host Country: Czech RepublicJakub Hrazdira, Jakub Ondroušek

Special Notes: As half of the puzzles are variants on existing puzzles, the instructions for the variant puzzles will just contain the modifications to the rules.

1. Coins [Jakub Ondroušek] (23 points)Place one coin into each cell such that the sum of the coins in each row (and column) matches the number to the left (and the top). The valid denominations of coins are supplied with the puzzle; the same denomination may be used multiple times in each row (or column).

The size of the coins are only for cosmetic purposes. It is possible for any denomination to remain unused in the correct solution.

Answer: For each designated row, enter its contents from left to right. The content of each cell is the denomination of the coin in that cell.

Example Answer: 2052,221

2a

2b

31

105

40

5

9

8 30 35

3111

05001

4044

555

999

8 88 30 33 3335

31

105

40

5

9

8 30 35

20 10 2 1

5 5 1 50

2 5 5 20

1 50 20 5

2a

2b

72 27 13

80

27

5

50 20 10

20 5 2

2 2 1

1 2 5 10 20 50

Some diagonals are marked with a number, which represents the sum of all coins on that diagonal.


2. Coins (diagonal) [Jakub Ondroušek] (16 points)

1a

1b

105 13 9 130 17

22

10

77

54

111

2a

2b

30 30 30

30

60

30 50

30

60

100 20 30 50 100

30 0030 0030 00

3033

6066

30 00 50

30 00

60 00

000050 5530 3320 2200 0000 1111

30 30 30

30

60

30 50

30

60

100 20 30 50 100

2020ROUND 8WPF PUZZLE GP

3. Skyscrapers [Jakub Ondroušek] (12 points)

Place a number from 1 to X (integers only) into each cell so that each number appears exactly once in each row and column. (X is the number of cells in each row.) Each number represents a skyscraper of its respective height. The numbers outside the grid indicate how many skyscrapers can be seen in the respective row or column from the respective direction; smaller skyscrapers are hidden behind higher ones. Some numbers may already be filled in for you.

Answer: For each designated row, enter its contents from left to right. Do not include any numbers outside the grid.


The numbers outside the grid indicate how many skyscrapers can be seen in the respective diagonal from the respective direction; smaller skyscrapers are hidden behind higher ones. Skyscrapers of the same height hide each other.


3 1 2 4 2 4 3 1 4 2 1 3 1 3 4 2

3a

3b

2

1 4

22

11144444

2

1 4

4 5 3 1 2 5 4 1 2 3 1 2 4 3 5 2 3 5 4 1 3 1 2 5 4

5 3 3 4 3

4 2

3a

3b

4. Skyscrapers (diagonal) [Jakub Ondroušek] (26 points)

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

3a

3b

4a

4b 3

4 4

3 3

333

4 44444 4444

333333

3

4 4

3 3


5. Number Snake (orthogonal) [Jakub Ondroušek] (16 points)

Put a different number from 1 to N (N is the number of cells in the grid) into each cell.

If two cells contain consecutive numbers, then those two cells must have an edge in common.

Answer: For each designated row, enter its contents from left to right. Use only the last digit for two-digit numbers; e.g., use ‘0’ for the number 10.


If two cells contain consecutive numbers, then those two cells must have an edge or a corner in common.


5a

5b

15 1 8 11 6

16 15 9 1 14 10 2 8 11 13 7 3 12 6 5 4

5a

5b

6 1 15

6 5 4 3 7 16 1 2 8 15 14 13 9 10 11 12

6. Number Snake (diagonal) [Jakub Ondroušek] (28 points)

6a

6b

7 17 28 64 44 22 12 3 62 47 11 32 1 34 55 40

5a

5b

26 64 22 31 1 58 14 43


7. Hitori [Jakub Ondroušek] (27 points)

Remove some numbers from the grid so that all remaining numbers are connected orthogonally and no two removed numbers are adjacent orthogonally.

Additionally, for each diagonal (including short diagonals), the remaining numbers must be all different.

Remove some numbers from the grid so that all remaining numbers are connected orthogonally and no two removed numbers are adjacent orthogonally. Additionally, for each row and each column, the remaining numbers must be all different.

The numbers on top of the diagram are for Answer purposes only.

Answer: For each row from top to bottom, enter the number (on top) of the second column from the left that has a removed number. Use only the last digit for two-digit numbers; e.g., use ‘0’ if the second removed number appears in column 10. If fewer than two of the numbers in the row are removed, enter ‘0’.

Example Answer: 40050

Example Answer: 030044

5 1 3 1 2 3 4 4 5 1 2 3 1 2 2 2 1 4 2 4 1 5 3 3 3

0 3 0 0 4

1 2 3 4 5

4

4 4 3 2 1 5 1 4 3 2 4 3 2 5 3 2 3 2 1 2 1 3 5 2 4

4 0 0 5 0

1 2 3 4 5

8. Hitori (diagonal) [Jakub Ondroušek] (40 points)

7

8 3 7 5 2 3 4 6 7 1 2 4 9 3 1 7 6 8 5 3 7 2 4 1 6 9 8 5 10 6 1 10 3 4 7 6 10 9 3 2 9 4 5 6 2 5 2 8 1 10 6 5 1 9 3 8 9 4 6 8 5 7 2 10 8 1 5 6 2 3 4 9 10 3 2 8 3 1 7 5 3 6 9 8 10 7 1 3 9 4 7 1 6 10 5 9 2 1 4 8

1 2 3 4 5 6 7 8 9 0

8

9 9 5 3 10 10 5 5 1 2 7 1 9 4 5 6 3 7 4 2 7 2 8 3 1 2 5 7 3 2 8 2 8 5 8 8 3 9 1 9 4 2 3 1 10 10 6 8 8 10 1 6 4 8 9 7 4 1 4 2 8 2 9 1 2 7 4 9 7 8 7 7 5 5 1 6 10 8 1 4 8 10 9 8 3 3 3 3 2 2 3 3 3 10 1 7 8 5 6 1

1 2 3 4 5 6 7 8 9 0


9. Masyu [Jakub Hrazdira] (5 points)

Draw a single loop that passes orthogonally through centers of cells. The loop must go through all circled cells. The loop may not intersect itself or enter the same cell more than once. The loop must go straight through the cells with white circles, with a turn in at least one of the cells immediately before or after each white circle. The loop must make a turn in all the black circles, but must go straight in both cells immediately before and after each black circle.

Answer: For each designated row, enter the letter for each cell, from left to right. The letter for a cell is ‘I’ if the path goes straight through the cell, ‘L’ if the path turns in the cell, and ‘X’ if the path does not go through the cell. You may use other letters or numbers, as long as they are distinct.

Example Answer: LLXXX,LIILX

The positions of the circles are provided, but you must determine which circles are black and which circles are white.

The colors of circles alternate along the loop (black-white-black-white...).

Example Answer: IIXXII,IIIXLL

5a

5b

5a

5b

10. Masyu (blackened, alternating) [Jakub Hrazdira] (39 points)

9a

9b

10a

10b


11. Magnets [Jakub Ondroušek] (38 points)

The grid is partitioned into regions of two square cells each (note that only region borders are drawn). Put “positive” (+) and “negative” (–) symbols into some cells, at most one symbol per cell, such that each region either has two symbols or no symbols at all. Adjacent cells (even within a region) cannot contain the same symbol.

The numbers above and to the left of the grid indicate the exact number of symbols of the specified type that must be placed in each column or row, respectively. If a number is not given, there might be any number of symbols of the specified type.

The dots in cells are only used for entering your answer.

Answer: Enter the contents of each dotted cell, reading the dots from left to right. (Ignore which row the dots are in.) Use ‘P’ for a “positive” (+) symbol, ‘N’ for a “negative” (–) symbol, and ‘X’ for an empty cell. Alternatively, you may use any three characters instead of ‘PNX’ , as long as they are distinct.

Example Answer: PXPXNP

The numbers around the grid indicate the exact number of symbols of the specified type that must be placed in each diagonal. If a number is not given, there might be any number of symbols of the specified type.

Example Answer: XPNN + 2 0

– 0

1 0 1 1 1

X P N N13

– + – + + – + – – + – +

2 0 0

2 0 1 2 1

00002222 000000000000

0 0001122 11111000021122 11111

2 0 0

2 0 1 2 1

+ 2– 0 3

0 1

2 2

2 3

P X P X N P13

– + – + – + – – + – + + + – + – + –

12. Magnets (diagonal) [Jakub Ondroušek] (22 points)

+ 4 4 3 3 – 5 4 2 3 4 5 4 4

2 2 2 3 3 3

11

+–

12

1 1 1 3

4 3 1 1 2 1 2 4 3 1 1 5 3 1

113331

4444333

111111

22211

2224444

3335551111

333 11

1 1 1 3

4 3 1 1 2 1 2 4 3 1 1 5 3 1


13. Doppelblock [Jakub Hrazdira] (37 points)

Place either a block or a number from 1 to X (integers only) into each cell so that each number appears exactly once in each row and each column. (X is two fewer than the number of cells in each row.) Each row and each column will therefore have exactly two cells with blocks in them. The numbers outside the grid indicate the sum of the numbers between the two blocks in that row or column. Some cells may already be filled in for you.

Answer: For each designated row, enter its contents from left to right. Use ‘X’ to denote a block. Use only the last digit for two-digit numbers; e.g., use ‘0’ for the number 10. Do not include any given numbers outside the grid.

Example Answer: 21XX3,1X23X

9a

9b

3 1 2 2 1 3 2 3 1 1 2 3 3 2 1 2

2 0 4

6 5

Place either a block or a number from 1 to X (integers only) into each cell. (X is the number of cells in each row.) Each row and each column should have exactly two cells with blocks in them. The numbers outside the grid indicate the sum of the numbers between the two blocks in that row or column. Some cells may already be filled in for you.

The set of numbers in each row and column are the same and are for you to determine. Numbers may not repeat within a row or column.

Answer: For each designated row, enter its contents from left to right. Use ‘X’ to denote a block. Use only the last digit for two-digit numbers; e.g., use ‘0’ for the number 10. Do not include any given numbers outside the grid.

Example Answer: 52XX3,2XX35

9a

9b

3 2 5 5 2 3 5 3 2 2 3 5 3 5 2

5 5 3 10

5

14. Doppelblock (unknown set) [Jakub Hrazdira] (56 points)

13a

13b

10 16 14 9 18 15

17

6 19

21

14a

14b

21 18 15 12 9 6 3 6 15

8 0

5


15. Nurikabe [Jakub Hrazdira] (16 points)

Shade some empty (non-numbered) cells black (leaving the other cells white) so that the grid is divided into non-overlapping regions; cells of the same color are considered in the same region if they are adjacent along edges. Each given number must be in a white region that has the same area in cells as that number. Each white region must have exactly one given number. All black cells must be in the same region. No 2×2 group of cells can be entirely shaded black.

Answer: For each designated row, enter the lengths (number of cells) of the black segments from left to right. If there are no black cells in the row, enter a single digit ‘0’. Use only the last digit for two-digit numbers; e.g., use ‘0’ for a black segment of length 10.

Example Answer: 5,31,111

Each white region must have exactly two given numbers. The area of each white region (in cells) must be the sum of the two given numbers that are in that region.


4 3

3 4

3a

3a

3a

4 1 2 3

2 4 3a

3a

7

6 8 1 2 5 3 4 9

15a

15a

8 1 8 1 4 4

5 5

16a

16a

16. Nurikabe (pair sums) [Jakub Hrazdira] (22 points)


17. Nurikabe (symmetry) [Jakub Hrazdira] (83 points)The shape of each white region is rotationally symmetric (looks the same when rotated 180-degrees). The black region is not necessarily symmetric.


10 6

7 9 6

6 3 3

17a

17a

1 2

4

4 3

3a

3a

V

X

T

U

I

W

LP

Z

F

N

Y

Z W P F

F U N

I N F I N I T Y

18a

18b

18. Pentominous [Jakub Hrazdira] (39 points)

Divide the grid into pentominoes such that every cell in the grid is part of exactly one pentomino. Pentominoes of the same shape (rotations and reflections of a pentomino count as the same shape) cannot touch each other along an edge (but they may touch diagonally). Some letters are given in the grid. Each letter must be part of a pentomino with that letter’s shape. It

I I P F

9a

9b

is permissible for a pentomino to contain more than one letter. (It is possible for some pentomino shapes to never appear in the grid, or more than once.)

The letter-to-shape correspondence for pentominoes has been supplied for you.

The competition puzzle will have a black square that is not part of the grid.

Answer: For each designated row, enter the letter for the pentomino that each cell belongs to, from left to right.

Example Answer: IPPPI,IUFUI


19. Loop (pentomino walls, max lengths) [Jakub Hrazdira] (93 points)

Blacken some cells, and draw a single loop that passes orthogonally through centers of cells.

The black cells must form the shapes of 11 pentominoes. Each pentomino shape is used at most once, but can be rotated or reflected. Pentominoes cannot touch along edges or corners.

If a letter is given in the grid, it must be a black square that is part of the pentomino with that letter.

The loop must go through all non-black cells and cannot go through any black cells. The loop may not enter the same cell more than once.

5a

5b

1 2 8

3 4

F Z Y Z

N

W T

X V

The numbers above and to the left of the grid indicate the length of the longest straight section of the loop that is within that row or column, respectively. Length is measured in cell lengths between centers of cells. It is possible for the provided length to appear more than once along that row or column.

Answer: For each designated row, enter the letter for each cell, from left to right. The letter for a cell is ‘I’ if the loop goes straight through the cell, ‘L’ if the loop turns in the cell, and ‘X’ if the cell is black. You may use three other letters or numbers, as long as they are distinct.

Example Answer: XLLXLLLILLILI,XLLIXXLLXLLLL

19a

19b

3 2 1 2 4 4

0

1

5

Z

X V

W F T

P N

I

V

X

T

U

I

W

LP

Z

F

N

Y

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ROUND WPF PUZZLE COMPETITION BOOKLET