题目
Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false.
Each letter in the magazine string can only be used once in your ransom note.
Note:
You may assume that both strings contain only lowercase letters.
canConstruct("a", "b") -> false
canConstruct("aa", "ab") -> false
canConstruct("aa", "aab") -> true
解题思路
把magazine上的字符串放进map中，值是字符出现的数量，然后循环遍历ransom上的字符，如果map中有则值减一，如果没有或者值为0则返回false
代码
ransomNote.go
package _383_Ransom_Note
func CanConstruct(ransomNote string, magazine string) bool {
var magazineMap map[rune]int
magazineMap = make(map[rune]int)
magazineRune := []rune(magazine)
for _, v := range magazineRune {
magazineMap[v]++
}
ransomNoteRune := []rune(ransomNote)
for _, letter := range ransomNoteRune {
tmp, ok := magazineMap[letter]
if !ok || tmp <= 0 {
return false
} else {
magazineMap[letter]--
}
}
return true
}
测试
ransomNote_test.go
package _383_Ransom_Note
import "testing"
func TestCanConstruct(t *testing.T) {
var tests = []struct{
a string
b string
output bool
} {
{"aa", "ab", false},
}
for _, test := range tests {
ret := CanConstruct(test.a, test.b)
if ret == test.output {
t.Logf("pass")
} else {
t.Errorf("fail, want %+v, get %+v", test.output, ret)
}
}
}
