http://note.youdao.com/noteshare?id=035634268c472db6e6cd14296d92322a

pinyin_combination.go

func mergeBetweenWord(list [][]string) []string {
	if len(list) == 0 {
		return []string{}
	}

	levelResult := [][]string{}
	levelResult = append(levelResult, []string{""}) // 塞一个空，下面就不用进行判断是否空了

	count := 0
	for i, word := range list {
		newLevel := make([]string, 0, len(levelResult[i])*len(word))
		for _, upper := range levelResult[i] {
			for _, pinyin := range word {
				newLevel = append(newLevel, upper+pinyin)
				count++
			}
		}
		levelResult = append(levelResult, newLevel)
	}

	result := make([]string, 0, count)
	// 从1开始，因为0是上面主动塞的空
	for _, v := range levelResult[1:] {
		result = append(result, v...)
	}

	return result
}

func subFullPinyinList(list [][]string) []string {
	result := make([]string, 0, len(list)*len(list)/1)
	for i := 0; i < len(list); i++ {
		r := mergeBetweenWord(list[i:])
		result = append(result, r...)
	}
	return result
}

pinyin_combination_test.go

package search

import (
	"testing"

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

func TestEmptyList(t *testing.T) {
	result := subFullPinyinList([][]string{})
	assert.Equal(t, []string{}, result)
}

func Test1Word(t *testing.T) {
	xi := []string{"xi"}
	param := make([][]string, 0, 1)
	param = append(param, xi)
	result := subFullPinyinList(param)
	assert.Equal(t, []string{"xi"}, result)
}

func TestZhongGuo(t *testing.T) {
	zhong := []string{"zhong"}
	guo := []string{"guo"}
	param := make([][]string, 0, 2)
	param = append(param, zhong)
	param = append(param, guo)
	result := subFullPinyinList(param)
	assert.Equal(t, []string{"zhong", "zhongguo", "guo"}, result)
}

func TestXiZang(t *testing.T) {
	xi := []string{"xi"}
	zang := []string{"zang", "cang"}
	param := make([][]string, 0, 2)
	param = append(param, xi)
	param = append(param, zang)
	result := subFullPinyinList(param)
	assert.Equal(t, []string{"xi", "xizang", "xicang", "zang", "cang"}, result)
}

func TestXiZangQu(t *testing.T) {
	xi := []string{"xi"}
	zang := []string{"zang", "cang"}
	qu := []string{"qu", "ou"}
	param := make([][]string, 0, 15)
	param = append(param, xi)
	param = append(param, zang)
	param = append(param, qu)
	result := subFullPinyinList(param)
	expected := []string{"xi", "xizang", "xicang", "xizangqu", "xizangou",
		"xicangqu", "xicangou", "zang", "cang", "zangqu", "zangou",
		"cangqu", "cangou", "qu", "ou"}
	assert.Equal(t, expected, result)
}