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
sr4saurabh: 2020-02-20 20:44:26

hint: preprocessing and pattern!! write condensed code(700B is source limit)!!

aryan__0406: 2020-01-15 17:03:52

I dont know whats wrong with my code. I have checked every case with worst cases also. But wrong answer is coming here after submitting.what should i do

thoufond: 2020-01-02 13:19:53

i tried to write cycles of numbers from 0-9, but program exceeds 700 bytes,
shitty online judge

nastik: 2020-01-01 08:17:03

@ghazikhan13, because we need to get the last digit, and x %10 will give last digit of x.

thiyagumessi: 2019-12-09 11:25:20

Hint: make a list of last numbers for 0-9

janakiram_18: 2019-11-22 03:55:27

Modular exponentiation is throwing a TLE and i'm doing it in python

apshada: 2019-11-10 09:56:11

its just (a^b)mod 10

purplecs: 2019-10-06 12:18:11

use binary exponentiation

pyskmr: 2019-10-02 15:12:33

use fast exponentiation.

jitto777: 2019-09-13 06:42:50

good question though..

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