diff --git a/24_lexicographic_permutations/main.go b/24_lexicographic_permutations/main.go index 0f7fe42..8465e62 100644 --- a/24_lexicographic_permutations/main.go +++ b/24_lexicographic_permutations/main.go @@ -10,7 +10,7 @@ var nums = []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9} func main() { var facs []int for _, i := range nums { - n, _ := findPermutation(i, i) + n := findFacs(i) facs = append(facs, n) } fmt.Println("facs:", facs) @@ -30,13 +30,10 @@ func findNPermutation(n int, src []int, facs []int) string { return ret } -func findPermutation(n, m int) (int, error) { - if m > n { - return 0, fmt.Errorf("m=%d cannot be larger than n=%d", m, n) - } +func findFacs(n int) int { p := 1 - for i := n - m + 1; i <= n; i++ { + for i := 1; i <= n; i++ { p *= i } - return p, nil + return p } diff --git a/24_lexicographic_permutations/main_test.go b/24_lexicographic_permutations/main_test.go index c7150d9..ba4bc32 100644 --- a/24_lexicographic_permutations/main_test.go +++ b/24_lexicographic_permutations/main_test.go @@ -1,67 +1,44 @@ package main import ( - "errors" - "reflect" "testing" ) func Test_findPermutation(t *testing.T) { type args struct { n int - m int } tt := []struct { - name string - args args - want int - wantErr error + name string + args args + want int }{ { - "1-2", - args{1, 2}, - 0, - errors.New("m=2 cannot be larger than n=1"), - }, - { - "1-1", - args{1, 1}, + "1", + args{1}, 1, - nil, }, { - "3-3", - args{3, 3}, + "2", + args{1}, + 2, + }, + { + "3", + args{3}, 6, - nil, }, { - "4-4", - args{4, 4}, + "4", + args{4}, 24, - nil, - }, - { - "3-2", - args{3, 2}, - 6, - nil, - }, - { - "4-2", - args{4, 2}, - 12, - nil, }, } for _, tc := range tt { t.Run(tc.name, func(t *testing.T) { - got, err := findPermutation(tc.args.n, tc.args.m) - if !reflect.DeepEqual(err, tc.wantErr) { - t.Errorf("findPermutation() = %v, want err %v", err, tc.wantErr) - } + got := findFacs(tc.args.n) if got != tc.want { - t.Errorf("findPermutation() = %v, want %v", got, tc.want) + t.Errorf("findFacs() = %v, want %v", got, tc.want) } }) } diff --git a/32_pandigital_products/main.go b/32_pandigital_products/main.go new file mode 100644 index 0000000..13d4f21 --- /dev/null +++ b/32_pandigital_products/main.go @@ -0,0 +1,40 @@ +package main + +import ( + "fmt" + "sort" + "strconv" +) + +func main() { + sum := 0 + for i := 0; i < 10000; i++ { + if hasPandigitalProduct(i) { + sum += i + } + } + fmt.Println("sum:", sum) +} + +func hasPandigitalProduct(n int) bool { + for i := 1; i <= n; i++ { + for n%i == 0 && isPandigital(strconv.Itoa(n)+strconv.Itoa(i)+strconv.Itoa(n/i)) { + fmt.Printf("Pandigital:%d = %d * %d\n", n, i, n/i) + return true + } + } + return false +} + +func isPandigital(s string) bool { + var ss []string + for _, c := range s { + ss = append(ss, string(c)) + } + sort.Strings(ss) + s = "" + for _, c := range ss { + s += c + } + return s == "123456789" +} diff --git a/32_pandigital_products/main_test.go b/32_pandigital_products/main_test.go new file mode 100644 index 0000000..5997479 --- /dev/null +++ b/32_pandigital_products/main_test.go @@ -0,0 +1,63 @@ +package main + +import ( + "testing" +) + +func Test_isPandigital(t *testing.T) { + type args struct { + s string + } + tests := []struct { + name string + args args + want bool + }{ + { + "912345678", + args{"912345678"}, + true, + }, + { + "12345678", + args{"12345678"}, + false, + }, + { + "812349756", + args{"812349756"}, + true, + }, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := isPandigital(tt.args.s); got != tt.want { + t.Errorf("isPandigital() = %v, want %v", got, tt.want) + } + }) + } +} + +func Test_hasPandigitalProduct(t *testing.T) { + type args struct { + n int + } + tests := []struct { + name string + args args + want bool + }{ + { + "7254", + args{7254}, + true, + }, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := hasPandigitalProduct(tt.args.n); got != tt.want { + t.Errorf("hasPandigitalProduct() = %v, want %v", got, tt.want) + } + }) + } +}