Fancy That!

3.3

3 votes
Algorithms, Dynamic Programming, Medium
Problem

Misha has decided to come up with the following puzzle to ask her friends:

Find the count of fancy numbers in the range [L,R]. Fancy numbers have an interesting property. The property states that the sum of numbers got as the result of adding all the subsequences that can be formed from the given number will be even.

For example, the number 202 is a fancy number as the sum of numbers that are formed by all of its subsequences is calculated as: 2+0+2+20+02+22+202=250. Since 250 is an even number, the number 202 is considered to be fancy.

Input format

  • First line: An integer T denoting the number of test cases
  • Each of the next  T lines: Two space-separated integers L and R


Output format

  • Print the answer for each test case in a separate line.

Constraints

1T100

1L, R1010

Time Limit: 1
Memory Limit: 256
Source Limit:
Explanation

Subsequence Sum for 8 is 8  which is even.
Subsequence Sum for 9 is 9 which is odd.
Subsequence Sum for 10 is 11 (10+1+0) which is odd.
Subsequence Sum of 11 is 13 (11+1+1) which is odd.

Hence, there is only one number in the range [8,11] which is fancy.

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