hdu 1708 Fibonacci String

#include<iostream>
#include<string>
using namespace std;
char ch1[100], ch2[100];
int a[50][123];

int main()
{
int t;
scanf("%d", &t);
while(t--)
{
getchar();
int m, i, j;
memset(a, 0, sizeof(a));
scanf("%s%*c%s%d", ch1, ch2, &m);
for( i=0; ch1[i] != '\0'; i++)
a[0][ch1[i]]++;
for( i=0; ch2[i] != '\0'; i++)
a[1][ch2[i]]++;
for( i=2; i <= m; i++ )
{
for( j=97; j <= 127; j++)
a[i][j] = a[i-1][j] + a[i-2][j];
}
for( i=97; i <= 122; i++)
printf("%c:%d\n", i, a[m][i]);
printf("\n");
}
return 0;
}