47 lines
1.0 KiB
C++
47 lines
1.0 KiB
C++
#include <stdio.h>
|
|
|
|
int not_prime[1000000] = {0};
|
|
// 0 -> prime, 1 -> prime
|
|
|
|
int main() {
|
|
not_prime[0] = 1;
|
|
not_prime[1] = 1;
|
|
int i = 2;
|
|
while (i < 1000) {
|
|
if (not_prime[i] == 1) {
|
|
i++;
|
|
continue;
|
|
}
|
|
int cur = i * i;
|
|
while (cur < 1000000) {
|
|
not_prime[cur] = 1;
|
|
cur += i;
|
|
}
|
|
i++;
|
|
}
|
|
|
|
for (int n = 1; n <= 100; n++) {
|
|
bool found = false;
|
|
for (int i = 1; i <= 9999; i += 2) {
|
|
int cat = 0;
|
|
if (i < 10) {
|
|
cat = n * 10 + i;
|
|
} else if (i < 100) {
|
|
cat = n * 100 + i;
|
|
} else if (i < 1000) {
|
|
cat = n * 1000 + i;
|
|
} else {
|
|
cat = n * 10000 + i;
|
|
}
|
|
if (!not_prime[cat]) {
|
|
printf("%d,", cat);
|
|
found = true;
|
|
break;
|
|
}
|
|
}
|
|
if (!found) {
|
|
printf("\n%d failed\n", n);
|
|
}
|
|
}
|
|
return 0;
|
|
} |