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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.
Input
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.
Output
For each test case output an integer per line representing the result.
Example
Input: 2 3 10 6 2 Output: 9 6
Added by: | Jose Daniel Rodriguez Morales |
Date: | 2008-12-01 |
Time limit: | 1s |
Source limit: | 700B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: GOSU |
Resource: | Own |
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2019-11-22 03:55:27
Modular exponentiation is throwing a TLE and i'm doing it in python |
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2019-11-10 09:56:11
its just (a^b)mod 10 |
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2019-10-06 12:18:11
use binary exponentiation |
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2019-10-02 15:12:33
use fast exponentiation. |
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2019-09-13 06:42:50
good question though.. |
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2019-08-03 20:23:22
@ghazikhan13 to get last digit . for example do 346 %10 and your output will be 6 |
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2019-07-17 13:17:46
hey guys, can anyone tell me why everyone did modules division by 10 only, why not any other number ?? Last edit: 2019-07-17 14:08:23 |
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2019-07-09 05:46:21
Just think like Big_Mod algorithm i or find pattern you will get answer |
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2019-07-08 11:05:21
For all those who are getting WA after considering a=0,b=0 case also its due to pow() function here input is non_primitive so we cant use pow function it will not return the required value PS: even i dont how we can know input is primitive or non primitive if somebody know pls tell me also |
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2019-07-07 17:07:55
Hint: This can be done in O(1) time, just look for patterns in last digits, they will repeat somehow, somewhere :-) |