PR003004  Digit Sum
For a pair of integers a and b, the digit sum of the interval [a,b] is defined as the sum of all digits occurring in all numbers between (and including) a and b. For example, the digit sum of [28, 31] can be calculated as:
2+8 + 2+9 + 3+0 + 3+1 = 28
Given the numbers a and b, calculate the digit sum of [a,b].
Input
On the first line one positive number: the number of test cases, at most 100.
After that per test case:
 one line with two spaceseparated integers, a and b (0 <= a <= b <= 10^15).
Output
Per test case:
 one line with an integer: the digit sum of [a,b];
Example
Input: 3 0 10 28 31 1234 56789 Output: 46 28 1128600
hide comments
abhishen99:
20201224 13:15:36
easy peasy ... 

vyavaharesid:
20200520 16:13:01
can anyone help me iam getting tle tried code of gfg digit sum plz give any link for studying 

rul0:
20200209 20:05:37
this problem have something rare. I have the same situation as dwij28, 3 comments below 

ca999:
20191205 11:20:16
Hmm weird, I got WA for CRCRC1C, but got AC for this one with literally the same code. 

Akshay Aradhya:
20180204 13:04:47
LOL I forgot to change my DP memory from CPCRC1C.


dwij28:
20160629 11:58:48
Answer should technically always fit in the range of long long int. But my C++ solution gives a WA but its exact 100% translation into python gives AC. Can someone tell me what could be the reason behind it ? 

nitin jain:
20160123 19:22:45
just ctrl c and ctrl v !! CPRC1C 

sonupmandal:
20160123 19:18:37
copy paste CPCRC1C and got AC in one go......:) 

Yash:
20150704 17:01:24
CPCRC1C accepted but NZEC here :( 

fitcat:
20131128 05:39:02
Same as CPCRC1C except with higher upper limit. 
Added by:  kojak_ 
Date:  20131125 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 
Resource:  BAPC 