UVA 294 294 - Divisors (数论)

UVA 294 - Divisors

#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;

const int N = 35005;
int prime
, pn = 0, vis
;
int t, a, b;

int cal(int num) {
int ans = 1;
for (int i = 0; i < pn && prime[i] <= num; i++) {
if (num % prime[i]) continue;
int count = 1;
while (num % prime[i] == 0) {
count++;
num /= prime[i];
}
ans *= count;
}
return ans;
}

void solve() {
int ans, Max = 0;
for (int i = a; i <= b; i++) {
if (Max < cal(i)) {
ans = i;
Max = cal(i);
}
}
printf("Between %d and %d, %d has a maximum of %d divisors.\n", a, b, ans, Max);
}

int main() {
for (int i = 2; i < N; i++) {
if (vis[i]) continue;
prime[pn++] = i;
for (int j = i; j < N; j += i)
vis[j] = 1;
}
scanf("%d", &t);
while (t--) {
scanf("%d%d", &a, &b);
solve();
}
return 0;
}