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
Sameer Anand: 2020-10-14 18:01:15

Guys, the value of 'b' CAN be zero in the problem. I don't know why would the asker specifically say the opposite in the problem statement. Wasted my 2 hours.

bodo2: 2020-10-09 02:38:04

why it is saying "Your solution is too long for this problem, the limit is 700 bytes!"
any solution

naveen1948: 2020-10-03 13:10:30

dont directly compute a power b it will not work and will show run time error as the time required to calculate for large numbers is more

ayan_v: 2020-10-02 06:33:20

used Euler totient function gave the right answer but the compiler not accepting

saquelain: 2020-09-29 06:14:25

compute mod 10 in power funtion

whiterose000: 2020-09-22 16:09:19

I am using modular binary exponentiation in this problem but it gives me 700 bytes error and says my program is using much more space then this. please help!!

shantanu_25: 2020-09-17 16:57:08

I think here "a and b both are not 0" means both are not 0 at the same time.

rudra_hari007: 2020-09-15 07:33:03

Can anyone tell why normal solution is not working?

jinks: 2020-09-05 16:55:26

I'm new to SPOJ, I've submitted my solution but it crossed the memory limit of 70 bytes. How did you guys manage to solve it in less than 700 bytes?

thepankj: 2020-08-17 09:17:46

Misleading statement 'a and b both are not 0'.
Make sure you account for b = 0 in your code.

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