From 19da2f10c6e999c0106b6be8862c3f0bbd68dd44 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Fri, 26 Aug 2016 04:18:56 +0200 Subject: Sovle pascal triangle --- go/pascals-triangle/README.md | 33 +++++++++++++++++++ go/pascals-triangle/pascals_triangle.go | 16 +++++++++ go/pascals-triangle/pascals_triangle_test.go | 49 ++++++++++++++++++++++++++++ 3 files changed, 98 insertions(+) create mode 100644 go/pascals-triangle/README.md create mode 100644 go/pascals-triangle/pascals_triangle.go create mode 100644 go/pascals-triangle/pascals_triangle_test.go (limited to 'go/pascals-triangle') diff --git a/go/pascals-triangle/README.md b/go/pascals-triangle/README.md new file mode 100644 index 0000000..bf36935 --- /dev/null +++ b/go/pascals-triangle/README.md @@ -0,0 +1,33 @@ +# Pascals Triangle + +Write a program that computes Pascal's triangle up to a given number of rows. + +In Pascal's Triangle each number is computed by adding the numbers to +the right and left of the current position in the previous row. + +```plain + 1 + 1 1 + 1 2 1 + 1 3 3 1 +1 4 6 4 1 +# ... etc +``` + +To run the tests simply run the command `go test` in the exercise directory. + +If the test suite contains benchmarks, you can run these with the `-bench` +flag: + + go test -bench . + +For more detailed info about the Go track see the [help +page](http://exercism.io/languages/go). + +## Source + +Pascal's Triangle at Wolfram Math World [http://mathworld.wolfram.com/PascalsTriangle.html](http://mathworld.wolfram.com/PascalsTriangle.html) + +## Submitting Incomplete Problems +It's possible to submit an incomplete solution so you can see how others have completed the exercise. + diff --git a/go/pascals-triangle/pascals_triangle.go b/go/pascals-triangle/pascals_triangle.go new file mode 100644 index 0000000..613185e --- /dev/null +++ b/go/pascals-triangle/pascals_triangle.go @@ -0,0 +1,16 @@ +package pascal + +func Triangle(n int) [][]int { + line := func(n int) []int { + l := []int{1} + for k := 1; k <= n; k++ { + l = append(l, l[k-1]*(n-k+1)/(k)) + } + return l + } + t := [][]int{} + for i := 0; i < n; i++ { + t = append(t, line(i)) + } + return t +} diff --git a/go/pascals-triangle/pascals_triangle_test.go b/go/pascals-triangle/pascals_triangle_test.go new file mode 100644 index 0000000..955c7af --- /dev/null +++ b/go/pascals-triangle/pascals_triangle_test.go @@ -0,0 +1,49 @@ +package pascal + +import ( + "fmt" + "reflect" + "testing" +) + +var t20 = [][]int{ + {1}, + {1, 1}, + {1, 2, 1}, + {1, 3, 3, 1}, + {1, 4, 6, 4, 1}, + {1, 5, 10, 10, 5, 1}, + {1, 6, 15, 20, 15, 6, 1}, + {1, 7, 21, 35, 35, 21, 7, 1}, + {1, 8, 28, 56, 70, 56, 28, 8, 1}, + {1, 9, 36, 84, 126, 126, 84, 36, 9, 1}, + {1, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1}, + {1, 11, 55, 165, 330, 462, 462, 330, 165, 55, 11, 1}, + {1, 12, 66, 220, 495, 792, 924, 792, 495, 220, 66, 12, 1}, + {1, 13, 78, 286, 715, 1287, 1716, 1716, 1287, 715, 286, 78, 13, 1}, + {1, 14, 91, 364, 1001, 2002, 3003, 3432, 3003, 2002, 1001, 364, 91, 14, 1}, + {1, 15, 105, 455, 1365, 3003, 5005, 6435, 6435, 5005, 3003, 1365, 455, 105, 15, 1}, + {1, 16, 120, 560, 1820, 4368, 8008, 11440, 12870, 11440, 8008, 4368, 1820, 560, 120, 16, 1}, + {1, 17, 136, 680, 2380, 6188, 12376, 19448, 24310, 24310, 19448, 12376, 6188, 2380, 680, 136, 17, 1}, + {1, 18, 153, 816, 3060, 8568, 18564, 31824, 43758, 48620, 43758, 31824, 18564, 8568, 3060, 816, 153, 18, 1}, + {1, 19, 171, 969, 3876, 11628, 27132, 50388, 75582, 92378, 92378, 75582, 50388, 27132, 11628, 3876, 969, 171, 19, 1}, +} + +func TestTriangle(t *testing.T) { + for n := 1; n <= 20; n++ { + res := Triangle(n) + want := t20[:n] + if !reflect.DeepEqual(res, want) { + t.Fatalf("Triangle(%d) = %s,\nwant:%s\n", + n, format(res), format(want)) + } + } + t.Log(format(Triangle(20))) +} + +func format(t [][]int) (s string) { + for _, r := range t { + s = fmt.Sprintf("%s\n%v", s, r) + } + return +} -- cgit v1.2.3