PAT(B)1012. 数字分类 (20)

#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
int n, num;
int a[6] = { 0 };
int b = 1;
int ct1 = 0,  ct2 = 0;

cin >> n;
while (n--){
cin >> num;

if (num % 10 == 0) a[1] += num;
if (num % 5 == 1) {
++ct1;
a[2] += b*num; b = -b;
}
if (num % 5 == 2) ++a[3];
if (num % 5 == 3){
++ct2;
a[4] += num;
}
if (num % 5 == 4){
if (num > a[5]) a[5] = num;
}
}
double a4 = 1.0 * a[4] / ct2;
for (int i = 1; i < 6; ++i){
if (i>1) cout << " ";
if (a[i] == 0) {
if (i == 2 && ct1 > 0) {      //用a[i]==0判断时，a[2]里面可能经过多次正负相加得到0，从而误输出“N”
cout << "0"; continue;
}
cout << "N"; continue;
}
if (i == 4) {
cout << fixed << setprecision(1) << a4; continue;
}
cout << a[i];
}

return 0;
}