UVa 11572 Unique snowflakes【滑动窗口】

 1 #include<iostream>  
 2 #include<cstdio>  
 3 #include<cstring> 
 4 #include <cmath> 
 5 #include<stack>
 6 #include<vector>
 7 #include<map>
 8 #include<set> 
 9 #include<queue> 
10 #include<algorithm>  
11 #define mod=1e9+7;
12 using namespace std;
13 
14 typedef long long LL;
15 const int maxn=1000000+5;
16 int a[maxn];
17 
18 int main(){
19     int t,n;
20     scanf("%d",&t);
21     while(t--){
22         scanf("%d",&n);
23         for(int i=0;i<n;i++) scanf("%d",&a[i]);
24         
25         set<int> s;
26         int l=0,r=0,ans=0;
27         while(r<n){
28             while(r<n&&!s.count(a[r])) s.insert(a[r++]);
29             ans=max(ans,r-l);
30             s.erase(a[l++]);
31         }
32         printf("%d\n",ans);
33     }
34     return 0;
35 }