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
selfcoder24: 2019-06-12 09:31:04

use modular exponentiation with mod being 10 to fetch last digit.

kocko: 2019-06-09 18:53:09

Quite stupid requirement for the source code size....

motormouthdoda: 2019-05-28 23:12:42

Don't use binary exponentiation. The solution is O(1)

mubasshir00: 2019-05-21 20:39:42

use Binary Exponentiation.

sahruz_riyad: 2019-05-20 14:12:36

a and b both are not zero. But separatedly can be zero.. be careful about that

Last edit: 2019-05-20 14:13:04
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.

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