1063 计算谱半径 (20分)

#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
bool cmp(int a,int b){
    return a>b;
}
using namespace std;
int main(){
    int n;
    cin >> n;
    double a,b;
    vector<double> v(n);
    for (int i=0;i<n;i++){
        cin >> a >> b;
        v.push_back(a*a+b*b);
    }
    sort(v.begin(),v.end(),cmp);
    printf("%.2f",sqrt(v[0]));
    return 0;
}