AcWing 4483. 格斗场

image.png :::info i在前，j在后的例题 ::: 思路：
排序 + 双指针

  1. static int N = 200010;
  2. static int[] a = new int[N];
  3. static int n;
  4. static void solve() {
  5.     n = ni();
  6.     int k = ni();
  7.     for (int i = 0; i < n; i++)
  8.         a[i] = ni();
  9.     Arrays.sort(a, 0, n);
  10.     int cnt = n;
  11.     for (int i = 0, j = 0; i < n; i++) {
  12.         while (j < n && a[j] - a[i] <= k)
  13.             j++;
  14.         if (a[j - 1] > a[i])
  15.             cnt--;
  16.     }
  17.     out.println(cnt);
  18. }