diff --git a/exercises/practice/saddle-points/.docs/instructions.md b/exercises/practice/saddle-points/.docs/instructions.md index 920ecffe..c585568b 100644 --- a/exercises/practice/saddle-points/.docs/instructions.md +++ b/exercises/practice/saddle-points/.docs/instructions.md @@ -1,25 +1,26 @@ # Instructions -Detect saddle points in a matrix. +Your task is to find the potential trees where you could build your tree house. -So say you have a matrix like so: +The data company provides the data as grids that show the heights of the trees. +The rows of the grid represent the east-west direction, and the columns represent the north-south direction. -```text - 1 2 3 - |--------- -1 | 9 8 7 -2 | 5 3 2 <--- saddle point at row 2, column 1, with value 5 -3 | 6 6 7 -``` - -It has a saddle point at row 2, column 1. +An acceptable tree will be the largest in its row, while being the smallest in its column. -It's called a "saddle point" because it is greater than or equal to every element in its row and less than or equal to every element in its column. +A grid might not have any good trees at all. +Or it might have one, or even several. -A matrix may have zero or more saddle points. +Here is a grid that has exactly one candidate tree. -Your code should be able to provide the (possibly empty) list of all the saddle points for any given matrix. +```text + 1 2 3 4 + |----------- +1 | 9 8 7 8 +2 | 5 3 2 4 <--- potential tree house at row 2, column 1, for tree with height 5 +3 | 6 6 7 1 +``` -The matrix can have a different number of rows and columns (Non square). +- Row 2 has values 5, 3, 2, and 4. The largest value is 5. +- Column 1 has values 9, 5, and 6. The smallest value is 5. -Note that you may find other definitions of matrix saddle points online, but the tests for this exercise follow the above unambiguous definition. +So the point at `[2, 1]` (row: 2, column: 1) is a great spot for a tree house. diff --git a/exercises/practice/saddle-points/.docs/introduction.md b/exercises/practice/saddle-points/.docs/introduction.md new file mode 100644 index 00000000..34b2c77e --- /dev/null +++ b/exercises/practice/saddle-points/.docs/introduction.md @@ -0,0 +1,11 @@ +# Introduction + +You plan to build a tree house in the woods near your house so that you can watch the sun rise and set. + +You've obtained data from a local survey company that show the height of every tree in each rectangular section of the map. +You need to analyze each grid on the map to find good trees for your tree house. + +A good tree is both: + +- taller than every tree to the east and west, so that you have the best possible view of the sunrises and sunsets. +- shorter than every tree to the north and south, to minimize the amount of tree climbing.