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
keshavsharma: 2016-12-11 19:46:14

getting time limit exceed :(

aditya930: 2016-12-09 05:58:01

#50....easy question AC in one go!

spartax: 2016-11-24 14:55:09

trivial. I did in theta(t) time complexity

pratik97: 2016-11-04 13:52:14

modular exponentiation

esshuvo: 2016-10-24 14:02:56

you can't get AC without getting some "error" :)

sreekanthkol: 2016-10-16 11:55:31

@timmy jose how do you generate your own test cases? I mean is there a tool that automatically does that?

sreekanthkol: 2016-10-16 11:53:07

@mhto you missed the corner case of b =0

sreekanthkol: 2016-10-16 11:30:13

@filip sollar the problem is simpler than you think. You used a for loop, no need to do that. I could tell you how but I don't want to spoil it for you.

Filip Sollar: 2016-10-14 02:44:44

can anyone help me ? solved using modular exponention even checked for case when b == 0 so my program doesnt crash but getting WA

srihari_v: 2016-10-07 20:59:27

no need of any bigmod algorithm

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