[用Golang刷LeetCode之 5] 500. Keyboard Row

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題目

問題連結：https://leetcode.com/problems/keyboard-row/#/description
Given a List of words, return the words that can be typed using letters of alphabet on only one row’s of American keyboard like the image below.

Example 1:
Input: ["Hello", "Alaska", "Dad", "Peace"]Output: ["Alaska", "Dad"]

Note:
You may use one character in the keyboard more than once.
You may assume the input string will only contain letters of alphabet.

思路

1. 用Map儲存字母到所在行的映射。
2. 變數words，對每一個單詞，先做小寫字母轉換存入word，再對word的每個字母進行遍曆。用flag標記是否是第一個字母，用row儲存第一個字母所在的行，對後續的字母，判斷其所在行是否等於row，若不是，直接跳出內層迴圈繼續判斷下一個單詞。考慮到數組需要預先設定長度，而數組長度未知，所以判斷整個單詞完畢後將其縣存入List，最後再把List的元素存入結果數組。

代碼

keyboardRow.go

package _500_Keyboard_Rowimport (    "fmt"    "strings")var alphabetMap map[string]intfunc init() {    alphabetMap = make(map[string]int)    row1 := []string{"q", "w", "e", "r", "t", "y", "u", "i", "o", "p"}    row2 := []string{"a", "s", "d", "f", "g", "h", "j", "k", "l"}    for _, v := range row1 {        alphabetMap[v] = 1    }    for _, v := range row2 {        alphabetMap[v] = 2    }}func findWord(word string) (ret bool) {    word = strings.ToLower(word)    var allRow int    allRow = alphabetMap[word[:1]]    length := len(word)    for i := 1; i < length; i++ {        row := alphabetMap[word[i:i+1]]        if allRow != row {            return false        }    }    return true}func FindWords(words []string) []string {    var ret []string    for _, v := range words {        ok := findWord(v)        if ok {            ret = append(ret, v)        }    }    fmt.Printf("ret:%+v\n", ret)    return ret}

測試

keyboardRow_test.go

package _500_Keyboard_Rowimport "testing"func TestFindWords(t *testing.T) {    words := []string{        "Hello", "Alaska", "Dad", "Peace"}    ret := FindWords(words)    wanted := map[string]int{        "Alaska": 1,        "Dad": 2,    }    for _, v := range ret {        _, ok := wanted[v]        if !ok {            t.Errorf("fail, not want but have %+v\n", v)            return        }    }    t.Logf("pass")}