WIP

想定解 (c++) (ytqm3 さんのコード)

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

int main(){
  ll k;
  cin>>k;
  ll x1,y1,x2,y2;
  cin>>x1>>y1>>x2>>y2;
  ll p=std::abs(x1-x2),q=std::abs(y1-y2);
  ll t=std::abs(p+q),u=std::abs(p-q);
  cout<<(t+2*k-1)/(2*k)+(u+2*k-1)/(2*k)<<endl;
}