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
kishlay1105: 2020-07-26 10:25:54

calculate (a^b)mod 10 using binary exponentiation .

dungeon_mr123: 2020-07-25 17:50:47

i cannot what is mistake in code please help

gokulan_cv: 2020-07-08 10:12:01

AC After 14 Times of failed submission. Python is horrible for CP. I think I should start learning c++.

[NG] This problem can be solved in 0.00s with Python. I think you should start learning to code.

Last edit: 2020-07-08 10:18:04
acktron: 2020-06-30 12:10:36

Solved in one go using modular exponentiation four :- (a ^ n) % 10 = ( ( (a % 10) ^ n);

br0ken_c0der: 2020-06-29 07:44:07

hint: Apply fast modular exponentiation using bitmasking.

samyak_maximus: 2020-06-27 12:34:31

by using binary exponentiation answer is obtained in my system ide but online judge is claiming that its a wrong answer. Kindly anyone help me through it _/\_

agrawaladitya: 2020-06-10 14:39:44

Turns out "a and b both are not 0" means that both are not simultaneously zero but can be individually zero

achin1tya_1977: 2020-06-09 08:48:34

700 Bytes how to resolve ?

samarthbtp1234: 2020-06-04 01:14:59

i cant find any mistake in my code pls hlp

Last edit: 2020-06-04 01:15:16
devesh_rs: 2020-05-30 05:45:25

stupid endl !!

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