PTA 乙级 1063 计算谱半径 (20分) C++

 1 #include<iostream>
 2 #include<cmath>
 3 
 4 using namespace std;
 5 
 6 int main() {
 7     int n = 0;
 8     double r;
 9     cin >> n;
10     for (int i = 0; i < n; ++i) {
11         int a = 0, b = 0;
12         double tmp = 0;
13         cin >> a >> b;
14         if (i == 0) r = sqrt(pow(a, 2) + pow(b, 2));
15         else tmp = sqrt(pow(a, 2) + pow(b, 2));
16         if (tmp > r) r = tmp;
17     }
18     printf("%.2f", r);
19     return 0;
20 }