题解 | 最大 FST 距离

#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    cin>>n;
    vector <long long> A;
    for(int i = 0; i < n; ++i){
        long long temp;
        cin>>temp;
        A.push_back(temp);
    }
    long long max_u = 0xffffffffffffffff;
    long long max_v = 0xffffffffffffffff;
    long long min_u = 0x7fffffffffffffff;
    long long min_v = 0x7fffffffffffffff;
    for(long long i = 0; i < n; ++i){
        long long temp_u = (i + 1) * (i + 1) + A[i] * A[i];
        long long temp_v = A[i] * A[i] - (i + 1) * (i + 1);
        if(temp_u > max_u)
            max_u = temp_u;
        if(temp_u < min_u)
            min_u = temp_u;
        if(temp_v > max_v)
            max_v = temp_v;
        if(temp_v < min_v)
            min_v = temp_v;
    }
        cout<<max(max_u - min_u, max_v - min_v);
}
// 64 位输出请用 printf("%lld")