LASTDIG - The last digit editorial - spoj - UCS - Unleash-Coding-Skills

Sunday, 8 April 2018

LASTDIG - The last digit editorial - spoj - UCS



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 
 
The link to this problem is: 


The approach is very simple
Note: If the last digit in the base is 0 or 1 or 6 or 5 then any power of that base is same as base
for others we can use the technique as shown in the code.You can simply understand the problem  by writing some examples in paper.

Solution in cpp

#include <iostream>
using namespace std;
int main() {
        long  int i,j,n,a,b;
cin>>n;
    for( i=0;i<n;i++)
    {
cin>>a>>b;
    long  int mod = b%4;
      long  int po = a%10;
      if(b==0)
      cout<<"1"<<endl;
      else if(a==0)
      cout<<"0"<<endl;
      else if(po==1||po==5||po==6||po==0)
        cout<<po<<endl;
        else{
          
            if(mod==1)
            {
              
               cout<<(po%10);
            }
            else if(mod==2)
            {
               cout<<((po*po)%10);
            }
            else if(mod==3)
            {
               cout<<((po*po*po)%10);
            }
            else{
               cout<<((po*po*po*po)%10);
            }
            cout<<endl;
        }
    }
}

Happy Coding..........

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