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
hide comments
adi_1996:
20160627 10:13:47
no modular exponentiation required... just the pattern ;) 

jayant choudhary:
20160621 16:06:21
there is no need for any modular exponentiation technicque or any technicque ...it's very simple problem .. :)


xinnix:
20160616 18:16:12
Wtf! Tried everything and checked every test case but still shows wrong answer.... Help me someone....


kp1994:
20160613 21:09:59
Use Exponential squaring for finding the power. 

kr_abhinav:
20160609 17:19:52
there is a possibility of an even faster algorithm. See for pattern in first digit after exponentiation with increasing n :) 

v_ns:
20160605 23:21:09
wow!! learned a new way of solving, had to change algo 2 times to get to the answer in given constraints . 

code1monkey1:
20160602 15:10:47
spoj is giving error while submitting as it says that the solution takes more than 700 bytes ,


coderaashir:
20160530 14:46:39
It says 0 <= b and a so they can be equal. 

manish3749:
20160525 23:00:34
awesome one... must solve....accepted in first go 

avisheksanvas:
20160518 11:41:08
https://crypto.stanford.edu/pbc/notes/numbertheory/exp.html

Added by:  Jose Daniel Rodriguez Morales 
Date:  20081201 
Time limit:  0.340s 
Source limit:  700B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  Own 