LASTDIG  The last digit
Nestor was doing the work of his math class about three days but he is tired of make operations a lot and he should deliver his task tomorrow. His math’s teacher gives him two numbers a and b. The problem consist of finding the last digit of the potency of base a and index b. Help Nestor with his problem. You are given two integer numbers: the base a (0 <= a <= 20) and the index b (0 <= b <= 2,147,483,000), a and b both are not 0. You have to find the last digit of a^{b}.
Input
The first line of input contains an integer t, the number of test cases (t <= 30). t test cases follow. For each test case will appear a and b separated by space.
Output
For each test case output an integer per line representing the result.
Example
Input: 2 3 10 6 2
Output: 9 6
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captaindavinci:
20171118 12:57:07
In this problem you could solve it by calculating (a ^ b) % 10, using fast modular exponentiation. Time complexity would be O(logb) 

sinersnvrsleep:
20171106 20:24:59
there occurs a pattern in the power of digits one needs to find that and its done 

sandilya1599:
20170927 08:12:53
python is love


mahilewets:
20170828 20:16:47
Very funny


mahilewets:
20170828 20:12:55
Python does the job 

softxide:
20170810 13:33:02
you can easily do the solution in O(4) space and O(4) time if you keep track of pattern in last digit .


larunrahul:
20170704 18:21:58
Hint: The pattern repeats for every 4 powers of last digit of 'a'. Such a simple but tricky one. Observe the pattern. 

manish_nit97:
20170630 21:03:50
power function will not work here. a^b can't be dealt with primitive data types. Use mathematical properties and that's it!! 

heybob:
20170628 20:55:48
Can someone explain the procedure to solve it without pow(). THanks 

coder_at_work:
20170626 07:56:13
Your source code shouldn't occupy more than 700 bytes, so remove unnecessary header files, whitespace etc. Easy problem, try to observe pattern. No need of using pow() function. 
Added by:  Jose Daniel Rodriguez Morales 
Date:  20081201 
Time limit:  1s 
Source limit:  700B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: GOSU 
Resource:  Own 