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二分，正反都掃一遍不連續K個不符條件即可

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream>
 4 #include <algorithm>
 5 #define INF 0x3f3f3f3f3f3f3f3f
 6 using namespace std;
 7 typedef long long LL;
 8 
 9 const int maxn = 2e5 + 10;
10 int A[maxn];
11 int ans[maxn];
12 int N, K;
 
13 
14 bool ck(int x) {
15     int cnt = K - 1;
16     for (int i = 0; i < N + 1 - K; i++) {
17         if (A[i + K - 1] - A[i] > x) {
18             cnt++;
19         } else {
20             cnt = 0;
21         }
22         if (cnt == K) return false;
23     }
24     cnt = K - 1;
25     for (int
 
 i = N - 1; i >= K - 1; i--) {
26         if (A[i] - A[i - K + 1] > x) {
27             cnt++;
28         } else {
29             cnt = 0;
30         }
31         if (cnt == K) return false;
32     }
33     return true;
34 }
35 
36 int main() {
37     scanf("%d%d", &N, &K);
38     for (int
 
 i = 0; i < N; i++) {
39         scanf("%d", &A[i]);
40     }
41     sort(A, A + N);
42     int dn = 0, up = A[N - 1] - A[0] + 1;
43     while (dn < up - 1) {
44         int mid = (up - dn) / 2 + dn;
45         if (ck(mid)) {
46             up = mid;
47         } else {
48             dn = mid;
49         }
50     }
51     printf("%d\n", dn == 0 ? dn : up);
52     return 0;
53 }
54 
55 
56 /*
57 4
58 2
59 -1 2 4 100
60 */

Gym 101510C-Computer Science