제가 작성한 문제 풀이. 반례 좀 부탁 드립니다.

#include<iostream>
#include<vector>
#include<algorithm>
#define MAX 20000000000
using namespace std;
vector<long long> arr;
long long N,M;
long long smaller(long long x,long long y){if(x<y){return x;}return y;}         
long long getMid(long long sp,long long ep){
     long long s=(sp+ep)/2,e=s+1,ret=MAX;
     while(s>=sp&&e<=ep){
                         if(arr[e]-arr[s]>=M){ret=arr[e]-arr[s];break;}
                         else{
                              if(s==sp){e+=1;}
                              else if(e==ep){s-=1;}
                              else{if(arr[s]-arr[s-1]<arr[e+1]-arr[e]){s-=1;}else{e+=1;}}
     }}
     return ret;
}
long long mkANS(long long sp,long long ep){
     long long ret=MAX;
     if(sp+1==ep){
                  if(arr[ep]-arr <M){ret=MAX;}
                  else{ret=arr[ep]-arr ;}
     }
     else if(sp==ep){ret=MAX;}
     else{
          ret=smaller(ret,mkANS(sp,(sp+ep)/2));
          ret=smaller(ret,mkANS((sp+ep)/2+1,ep));
          ret=smaller(ret,getMid(sp,ep));
     }
     return ret;
}
int main(void){
    long long i,temp;
    cin>>N>>M;
    for(i=0;i<N;i++){cin>>temp;arr.push_back(temp);}
    sort(arr.begin(),arr.end());
    cout<<mkANS(0,N-1)<<endl;
    return 0;
}