NOVICE43 - Problem 3
When I first learned backtracking I made a program to find all the permutations of the English alphabets in lexicographically increasing. Filled with elation I showed the program to Rohil. Rohil being someone who likes to do stuff off the league was not impressed and gave me the following variation of the problem help me to solve the problem:
You have to find the number of permutations of length N (1<=N<=11) such that at whenever an alphabet (say 'c' ) appears in the permutation all the alphabets smaller than 'c' should have appeared before it at least once. An alphabet is smaller than another if it appears before the other in the English alphabet. ‘a’ being the smallest and ‘z’ being the largest. For example when N=2 then aa, ab are the only valid permutations and ba, bb is invalid since in ba all the alphabets smaller than b have not appeared at least once before it. See example for further clarification.
Input
Line 1: T (number of test cases)
Line 2: n1
Line 3: n2
…
…
Output
Line 1: number of such permutations of length n1
…
...
Example
Input: 2 2 3 Output: 2 5
Explanation for N=3, the possible permutations are: abc, aba, abb, aab, aaa
hide comments
technophyle:
2013-06-22 03:25:59
The answer for N=11 is 6785** |
|
Rishikesh Jha:
2013-05-22 05:23:50
why is this problem in classical ?
|
|
Shubham Somani:
2012-12-15 11:43:54
If u cant do the math, then do the recursion :D |
|
Romal Thoppilan:
2012-07-09 14:14:47
Then whats the answer for n=11 , even i,m getting 182905 ... ? |
|
saket diwakar:
2012-01-10 11:25:20
@Aseem
|
|
Aseem Kumar:
2011-06-09 19:21:06
isn't the answer for N=11 1829** ? |
|
:D:
2011-04-23 19:18:02
yes |
|
Ikhaduri:
2011-04-23 16:08:35
will the answer fit into a 64 bit integer?
|
|
Mahesh Chandra Sharma:
2011-03-04 11:51:12
NOVICE43 specify that it is the 3rd problem of 4th Novice contest in which problems are always named by their index. And it doesn't look like a creativity contest though :-) |
|
hendrik:
2011-03-02 17:31:03
There is already a Problem 3 (NOVICE23).
|
Added by: | Mahesh Chandra Sharma |
Date: | 2011-03-01 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | NSIT Noivce contest #4 |