链接:https://leetcode-cn.com/problems/letter-combinations-of-a-phone-number
给定一个仅包含数字 2-9 的字符串,返回所有它能表示的字母组合。
给出数字到字母的映射如下(与电话按键相同)。注意 1 不对应任何字母。
示例:
输入:“23”
输出:[“ad”, “ae”, “af”, “bd”, “be”, “bf”, “cd”, “ce”, “cf”].
class Solution {
public List<String> letterCombinations(String digits) {
LinkedList ans=new LinkedList<>();
if(digits.isEmpty()) return ans;
String[]mapping=new String[]{"0","1","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
ans.add("");
while(((String) ans.peek()).length()!=digits.length()){
String remove=(String) ans.remove();
String map=mapping[digits.charAt(remove.length())-'0'];
for(char c:map.toCharArray()){
ans.addLast(remove+c);
}
}
return ans;
}
}