HDU 1286 找新朋友 (欧拉phi函数打表)

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;
const int maxn = 32768 + 5;
int phi[maxn+5];

void phi_table(int n){
    memset(phi, 0, sizeof(phi));
    phi[1] = 1;
    for(int i = 2; i <= n; ++i)  if(!phi[i])
        for(int j = i; j <= n; j += i){
            if(!phi[j])  phi[j] = j;
            phi[j] = phi[j] / i * (i-1);
        }
}

int main(){
    phi_table(maxn);
    int n, T;  cin >> T;
    while(T--){
        scanf("%d", &n);
        printf("%d\n", phi[n]);
    }
    return 0;
}