https://www.acmicpc.net/problem/1009 solution

distributedProcess.cpp

//https://www.acmicpc.net/problem/1009

#include <stdio.h>

int cache[8][4] = {
  {2,4,8,6},
  {3,9,7,1},
  {4,6,4,6},
  {5,5,5,5},
  {6,6,6,6},
  {7,9,3,1},
  {8,4,2,6},
  {9,1,9,1}
};

int lastComputer(int a, int b) {
  int result;

  a %= 10;

  if (a == 1) {
    return 1;
  } else if (a == 0) {
    return 10;
  } else {
    result = cache[a-2][(b-1)%4];
  }

  return result;
}

int main(void) {
  int T = 0;
  int a = 0, b = 0;
  scanf("%d", &T);

  while (T-- > 0) {
    scanf("%d %d", &a, &b);
    printf("%d\n", lastComputer(a, b));
  }

  return 1;
}