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
iceman0_0: 2019-05-17 15:47:28

//check for b=0

andyy143: 2019-04-04 18:28:09

careful with 0 0

hritwik: 2019-03-20 23:51:19

guys please check for

I got WA bcoz of them

ubc_123: 2019-03-17 11:46:25

Last edit: 2019-03-17 11:47:16
hemans19: 2019-03-06 14:53:59

Use modular exponentiation method , it will work.

saurav_paul: 2019-03-03 19:15:02

Accept in one go .
Tips : you can use modulo + pattern for solve it with time-complexity 0(1) :)

aj_254: 2019-02-26 14:37:58

if you want AC in python dont use pattern strategy use modulo ..

bitbeast18: 2019-01-18 15:26:23

Has anybody done it in python?

Even after a lot of optimization its giving TLE. Have to use C to get AC.

Last edit: 2019-01-18 15:27:29
adarsh313: 2019-01-06 10:43:39

AC in 2nd attempt

harshit_k007: 2018-12-27 14:36:19

yes AC in 3 attempts...plse check case for b=0 , it costed me 2 WA!!

Added by:Jose Daniel Rodriguez Morales
Time limit:1s
Source limit:700B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: GOSU