Letter Combinations of a Phone Number

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這是一個迴圈操作，如果重數太多，只能遞迴搜尋,不滿足條件return 或者else,剛才出錯了

 

public class Solution {
private String letters[] = {"","","abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
private List<String> ret=new ArrayList<String>();
public List<String> letterCombinations(String digits) {
if(digits.length()==0)
{
ret.add("");
return ret;

}

List<String> list=new ArrayList<String>();

char c[]=digits.toCharArray();
leeter(0,c,"");
return ret;


}
public void leeter(int lev,char c[],String s)
{
if(lev==c.length){ ret.add(new String(s));return;}
for(int i=0;i<letters[c[lev]-‘0‘].length();i++)
{
char c1=letters[c[lev]-‘0‘].charAt(i);
leeter(lev+1,c,s+c1);
}

}
}