I'm trying to solve this problem on SPOJ using inclusion-exclusion principle but I can't get the correct answer. My code
private static void solve(long n, long m, long a, long d) {
long[] values = new long[5];
for (int i = 0; i < 5; i++) {
values[i] = a + i*d;
}
long left, right, sum = 0, diff = m-n+1;
for (int i = 0; i < (2 << 5); i++) {
int count = 0;
long divisor = 1;
for (int j = 0; j < 5; j++) {
if ((i & (1 << j)) > 0) {
count++;
divisor = lcm(divisor, values[j]);
}
}
left = (n-1)/divisor;
right = m/divisor;
if (count % 2 == 0) sum -= right-left;
else sum += right - left;
}
System.out.println(diff-sum);
}