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authorDimitri Sokolyuk <demon@dim13.org>2016-08-26 04:18:56 +0200
committerDimitri Sokolyuk <demon@dim13.org>2016-08-26 04:18:56 +0200
commit19da2f10c6e999c0106b6be8862c3f0bbd68dd44 (patch)
tree6a49e4cc027eb42ebeca9271ac5fe1dee2bf9f95
parent0162fa190cdf0a3b7b5ce27855b7b67fd26278aa (diff)
Sovle pascal triangle
-rw-r--r--go/pascals-triangle/README.md33
-rw-r--r--go/pascals-triangle/pascals_triangle.go16
-rw-r--r--go/pascals-triangle/pascals_triangle_test.go49
3 files changed, 98 insertions, 0 deletions
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
+}