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 ab.


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.


For each test case output an integer per line representing the result.


3 10
6 2

Output: 9 6

hide comments
coderaashir: 2016-05-30 14:46:39

It says 0 <= b and a so they can be equal.

manish3749: 2016-05-25 23:00:34

awesome one... must solve....accepted in first go

avisheksanvas: 2016-05-18 11:41:08
Best explanation of Modular Exponentiation :).
Recursion with base case (b==0)

Last edit: 2016-05-18 11:41:39
vinu0103: 2016-05-17 14:35:53

learnt a new technique modular exponentiation

sayedathar11: 2016-05-06 18:32:19

ac in one go number theory rocks :)

walid_salah: 2016-03-28 21:35:22

It can be solved by quaternary numeral system ?

ianand: 2016-03-25 14:25:36

check for 12 2351357
if using fast modular exponentiation

Last edit: 2016-03-25 14:26:08
aru_674: 2016-03-23 10:48:29

b can be 0 please edit!!!

xtreampy: 2016-03-20 19:52:35

watch out when b(power) = 0

mhto: 2016-03-18 16:54:15

Tried with all possible test case, works fine on ideone. But SPOJ says wrong answer.
Help please Cant figure out what's wrong :(

Added by:Jose Daniel Rodriguez Morales
Time limit:0.340s
Source limit:700B
Memory limit:1536MB
Cluster: Cube (Intel G860)