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
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

rj_gupta: 2016-10-01 21:57:05

plz help me where i'm wrong

Last edit: 2016-10-01 21:58:24
sas1905: 2016-09-15 14:54:29

4 lines code in Java..:)

mat_79: 2016-09-12 14:33:26

Java has special function to do it well ;)

shamimice03: 2016-08-26 14:12:20

oka AC :) ... i use big mod algorithm for that :)
just find the modulas of 10;
as we know "6^2=36 the moduls of 36%10=6"

shamimice03: 2016-08-26 13:24:59

is it a big mod realted problem?

Added by:Jose Daniel Rodriguez Morales
Time limit:0.340s
Source limit:700B
Memory limit:1536MB
Cluster: Cube (Intel G860)