B题题解:
排序，然后check连续(不等)六项。
Code:

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,k;cin>>n>>k;
    int count=0, a[n+1];a[0]=0;
    for(int i=1;i<=n;i++) cin>>a[i];
    sort(a+1,a+1+n);
    for(int i=1;i<=n;i++) if(a[i]-a[i-1]<=k) 
    {
        if(a[i]!=a[i-1]) count++;
        if(count == 6) {cout<<"YES\n";return 0;}
    } else count=1;
    cout<<"NO\n";
    return 0;
}