#include "cross.h"
#include <algorithm>
long long SelectCross(int K, std::vector<int> I, std::vector<int> O) {
int N = I.size();
long long maxsize = 0;
std::vector<int> cha;
for(int i=0;i<N;i++){
cha.push_back(O[i]-I[i]);
}
if(K==1){
for(int i=0;i<N;i++){
long long now = (long long)O[i]*(long long)O[i] - (long long)cha[i]*(long long)cha[i];
maxsize = (maxsize>now)?maxsize:now;
}
} else{
std::vector<std::pair<int, int>> p;
for(int i=0;i<N;i++){
p.push_back(std::make_pair(O[i], cha[i]));
}
std::sort(p.begin(), p.end());
maxsize = (long long)p[K-1].first*(long long)p[K-1].first - (long long)p[K-1].second*(long long)p[K-1].second;
}
return maxsize;
}
