87 lines
1.9 KiB
Go
87 lines
1.9 KiB
Go
// Define two functions: (Two? Yes, sometimes we ask more out of Go.)
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//
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// // All returns a list of all substrings of s with length n.
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// All(n int, s string) []string
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//
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// // Frist returns the first substring of s with length n.
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// Frist(n int, s string) string
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//
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// Wait, is that a typo? It'll make sense if you do the bonus!
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//
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// Bonus exercise:
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//
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// Maybe we typed too fast. Once you get `go test` passing, try
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// `go test -tags asktoomuch`. (Hint, you can't make it happy.)
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//
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// Now slow down and do things right(tm). Define
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//
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// First(int, string) (first string, ok bool)
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//
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// spelling first correctly this time, and test with `go test -tags first`.
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package slice
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import (
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"reflect"
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"testing"
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)
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var allTests = []struct {
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n int
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s string
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out []string
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}{
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{1, "01234",
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[]string{"0", "1", "2", "3", "4"}},
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{1, "92834",
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[]string{"9", "2", "8", "3", "4"}},
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{2, "01234",
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[]string{"01", "12", "23", "34"}},
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{2, "98273463",
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[]string{"98", "82", "27", "73", "34", "46", "63"}},
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{2, "37103",
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[]string{"37", "71", "10", "03"}},
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{3, "01234",
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[]string{"012", "123", "234"}},
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{3, "31001",
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[]string{"310", "100", "001"}},
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{3, "982347",
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[]string{"982", "823", "234", "347"}},
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{4, "01234",
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[]string{"0123", "1234"}},
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{4, "91274",
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[]string{"9127", "1274"}},
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{5, "01234",
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[]string{"01234"}},
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{5, "81228",
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[]string{"81228"}},
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{6, "01234", nil},
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{len(cx) + 1, cx, nil},
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}
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var cx = "01032987583"
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func TestAll(t *testing.T) {
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for _, test := range allTests {
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switch res := All(test.n, test.s); {
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case len(res) == 0 && len(test.out) == 0:
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case reflect.DeepEqual(res, test.out):
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default:
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t.Fatalf("All(%d, %s) = %v, want %v.",
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test.n, test.s, res, test.out)
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}
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}
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}
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func TestFrist(t *testing.T) {
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for _, test := range allTests {
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if len(test.out) == 0 {
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continue
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}
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if res := Frist(test.n, test.s); res != test.out[0] {
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t.Fatalf("Frist(%d, %s) = %s, want %s.",
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test.n, test.s, res, test.out[0])
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}
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}
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}
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