sub_combination.go

package combination

// 对list求所有的子序列
// 比如：西藏区，西的拼音有：xi，藏的拼音有：zang,cang，区的拼音有：qu,ou
// 求出所有的子串：西，西藏，西区，西藏区，藏，藏区，区
// 的所有拼音组合
func subCombination(list [][]string) []string {
	if len(list) == 0 {
		return nil
	}

	results := list[0]
	for _, words := range list[1:] {
		tmpResult := make([]string, 0, len(results)*len(words))
		for _, result := range results {
			for _, word := range words {
				if len(word) == 0 {
					continue
				}
				tmpResult = append(tmpResult, result+word)
			}
		}
		results = append(results, tmpResult...)
	}

	return results
}

sub_combination_test.go

package combination

import (
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestSubCombinationEmpty(t *testing.T) {
	assert.Nil(t, subCombination(nil))
	assert.Nil(t, subCombination([][]string{}))
}

func TestSubCombinationXi(t *testing.T) {
	expected := []string{"xi"}
	actual := subCombination([][]string{[]string{"xi"}})
	assert.Equal(t, expected, actual)
}

func TestSubCombinationXiZang(t *testing.T) {
	expected := []string{"xi", "xizang", "xicang"}
	actual := subCombination([][]string{[]string{"xi"}, []string{"zang", "cang"}})
	assert.Equal(t, expected, actual)
}

func TestSubCombinationXiZangQu(t *testing.T) {
	expected := []string{"xi", "xizang", "xicang", "xiqu", "xiou", "xizangqu", "xizangou", "xicangqu", "xicangou"}
	actual := subCombination([][]string{[]string{"xi"}, []string{"zang", "cang"}, []string{"qu", "ou"}})
	assert.Equal(t, expected, actual)
}