Cod sursa(job #397862)
#include <stdio.h>
#include <math.h>
#include <string.h>
int ultimaCifra(int x)
{
int u = x % 10;
int mod = x % 4;
if(mod == 0) mod = 4;
return ((int)(pow(u, mod))) % 10;
}
int suma(int x)
{
int i, s = 0;
for(i = 1; i <= x; ++i) s += ultimaCifra(i);
return s % 10;
}
int v[101];
int main()
{
freopen("cifra.in", "r", stdin);
freopen("cifra.out", "w", stdout);
int t, l, x, i;
char n[101];
for(i = 0; i <= 100; ++i) v[i] = suma(i);
scanf("%d\n", &t);
while(t--)
{
scanf("%s\n", n);
l = strlen(n);
if(l == 1) x = (n[l - 1] - '0');
else x = (n[l - 2] - '0') * 10 + (n[l - 1] - '0');
printf("%d\n", v[x]);
}
return 0;
}