the same question i have asked in microsoft interview. (if it is the same :P)
for 12 perutation are (ad, ae, af, bd, be, bf, cd, ce ,cf); i have given them 3 solution(recusrsive, stack based) and the last one what they wanted. take a tertiary number(n) = 3^(number of digits) in case of 12 it is equals to 2; i m solving the save problem. assuming on every key there are only 2 alphabets. char c[][2] = {ab , cd, ......}; char n[] = 2156169 (number is pressed); so k = 7; for (i = 0; i < (1<<k); i++){ string s = ""; for (j = 0; j < k; j++){ s += c[n[j]][i & (1<<j)] } print(s); } same logic u can use for tertiary too. -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.