15.md

Letter Combinations of a Phone number

Practice

 void find(int ind,int a[],vector<string> keys,vector<string> &ans,string s,int n)
    {
        if(ind==n)
        {
            ans.push_back(s);
            return;
        }
        int x=a[ind];
        string st=keys[x];
        for(int i=0;i<st.size();i++)
        {
            s+=st[i];
            find(ind+1,a,keys,ans,s,n);
            s.pop_back();
        }
    }
    vector<string> possibleWords(int a[], int N)
    {
        //Your code here
        vector<string> ans;
        string s;
        
        vector<string> keys={"","","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz","",""};
        
        find(0,a,keys,ans,s,N);
        return ans;
    }
    ```