HARSHAD - Devlali Numbers
Devlali numbers were an important coinage by Indian recreational mathemtician D. R. Kaprekar.
For any positive integer n, define d(n) as the sum of n and the digits of n. Eg, d(199) = 199 + 1 + 9 + 9 = 218.
For a positive number m, if there exists no positive number r such that d(r) = m, then m is a Devlali number. First few Devlali numbers are 1, 3, 5, 7, ... so on.
A prime number falling in this family is called a Devlali Prime. First few Devlali Primes are 3, 5, 7, ... so on.
First line contains integer Q
Next Q lines contain two integers A and B
print Q lines, each listing number of Devlali Primes in range [A,B] (both inclusive)
1 <= Q <= 100000
0 <= A <= B <= 1000000
Input 3 1 3 0 10 5 8 Output 1 3 2
In c++ using cout & cin gave tle but acc using printf & scanf
Good problem. Applied several ideas after the first AC, surprised to find out what worked here and what did not. Strangely, problem very much in style of the other Piyush Kumar, from Delhi.
more testcases please with some big nmbers,testcase 5 wrong
good question....using stl the code length reduces to 1/4... :)
Jugal kishor sahu:
Finally done..!! Good ques.