# leetrcombination

```java
class Solution {
    public List<String> letterCombinations(String d) {
        
if(d.length()==0)
{
    return new ArrayList<>();
}
        
            String[] mp = {
                "",     // 0
                "",     // 1
                "abc",  // 2
                "def",  // 3
                "ghi",  // 4
                "jkl",  // 5
                "mno",  // 6
                "pqrs", // 7
                "tuv",  // 8
                "wxyz"  // 9
            };

            ArrayList<String> list=  new ArrayList<>();
            comb(d, 0, "", mp,list);
            System.out.print(list);
            return list;

    }



public static void comb(String d, int idx, String cur, String[] mp,ArrayList<String> list) {
       
             if(idx==d.length())
             {
                list.add(cur);
                return;
             }
           char ch= d.charAt(idx);  
           int pos= ch-'0';
           String ltr= mp[pos];
           for(int i=0;i<ltr.length();i++)
           {
               comb(d,idx+1,cur+ltr.charAt(i),mp,list);
           }
    }
}
```