A128503.水晶整理（最强解法）

时间最快，内存最小
我提交的时候是双100%

#include <cstdio>
#include <algorithm>
using namespace std;

const int MAXN = 200010;
int a[MAXN];

inline int read()
{
    int x = 0;
    char ch = getchar();
    while (ch != EOF && (ch < '0' || ch > '9'))
    {
        ch = getchar();
    }
    if(ch == EOF) return 0;
    while (ch >= '0' && ch <= '9')
    {
        x = x * 10 + (ch ^ 48);
        ch = getchar();
    }
    return x;
}

int main()
{
    int n = read();
    int k = read();
    for(int i = 0; i < n; i++)
    {
        a[i] = read();
    }
    sort(a, a + n);
    int r = n - 1, ans = 0;
    for(int i = n - 1; i >= 0; i--)
    {
        while(r > i && a[r] - a[i] > k) --r;
        if(a[r] <= a[i]) ans++;
    }
    printf("%d\n", ans);
    return 0;
}