題目：題目鏈接

思路：比賽中讀錯了題，題目要求選一個連續區間，卻讀成了隨便選取幾個櫃臺，英語要好好學啊，讀懂題就很簡單了，掃一遍就出結果了

AC代碼：

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstdlib>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <cstring>
 7 #include <vector>
 8 #include <string
 
>
 9 #include <queue>
10 #include <map>
11 #include <set>
12 
13 #define FRER() freopen("in.txt", "r", stdin);
14 #define INF 0x3f3f3f3f
15 
16 using namespace std;
17 
18 const int maxn = 1000000 + 5;
19 
20 vector<int> stand[maxn << 1];
21 
22 int brand[maxn], N, K;
 
23 
24 void init() {
25     for(int i = 0; i < (N << 1); ++i) 
26         stand[i].clear();
27     memset(brand, 0, sizeof(brand));
28 }
29 
30 int solve() {
31     int st = 0, ed = 0, ans = INF, k = 0, now = 0;
32     while(ed < (N << 1)) {
33         for(int i = 0; i < stand[ed].size(); ++i) {
 
34             ++now;
35             if(brand[stand[ed][i]] == 0)
36                 ++k;
37             ++brand[stand[ed][i]];
38         }
39         ++ed;
40         while(k == K && st < ed) {
41             ans = min(ans, now);
42             for(int i = 0; i < stand[st].size(); ++i) {
43                 --now;
44                 --brand[stand[st][i]];
45                 if(brand[stand[st][i]] == 0)
46                     --k;
47             }
48             ++st;
49         }
50     }
51     return ans == INF ? -1 : ans;
52 }
53 
54 int main()
55 {
56     //FRER()
57     while(~scanf("%d %d", &N, &K)) {
58         init();
59         int n, num;
60         for(int i = 0; i < N; ++i) {
61             scanf("%d", &n);
62             for(int j = 0; j < n; ++j) {
63                 scanf("%d", &num);
64                 stand[i].push_back(num);
65                 stand[i + N].push_back(num);
66             }
67         }
68         printf("%d\n", solve());
69     }
70     return 0;
71 }

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