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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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2015-10-17 02:34:17
hhh...If you have the problem of 700MB....you have to look for a solution near to yours... In fact, you can remarque that all the cases a%10(9cases) can be resumed into just one....mod 4 is the solution... just you have to take cases b==0 and a==0, each one alone, then b%=4; after that If b==0, you must put b=4 because when you look at case a%10==8, 8^0 is different from 8^4 Then you make b=pow(a, b)%10 and finally cout<<b<<'\n'; Last edit: 2015-10-17 02:34:59 |
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2015-10-11 10:13:41 satish
what's the idea @ Vivek |
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2015-10-07 20:16:25
"a and b both are not 0" This means that when a == 0 then b != 0; when b==0 then a != 0. A test case where a==0 and b==0 is excluded. |
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2015-09-29 15:37:34
Really easy sum....but it is saying wrong answer in this....but on my pc's compiler its working good...what is the reason? |
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2015-09-22 23:24:22 Vivek
Really easy.. You don't even Need to remember pattern of various digits such as for 3->3,9,7,1 and so on. was pending for 6 months.. 1 night simple idea, got AC in two mins. Last edit: 2015-09-22 23:28:40 |
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2015-09-12 17:12:22
every number repeats after a certain number times |
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2015-09-03 14:40:51 thirupathireddy
this is not good mentioning that both a and b not zero............. |
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2015-08-03 05:27:31 Mahesh Chaurasia
Please consider case a==0 and b==0; Considering them not together. |
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2015-07-25 16:52:31
@avid coder add a=a%10 ; //0<= a<=20 |
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2015-07-19 20:05:05 Avinash Bansal
check the test case when index=0, it cost me 1 WA |
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