poj 3320 尺取法

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <map>
 5 using namespace std;
 6 
 7 const int INF = 1111111;
 8 const int N = 1000000;
 9 int a[N];
10 map<int, int> mp;
11 
12 int main ()
13 {
14     int n;
15     while ( scanf("%d", &n) != EOF )
16     {
17         mp.clear();
18         for ( int i = 0; i < n; i++ )
19         {
20             scanf("%d", a + i);
21             mp[a[i]]++;
22         }
23         int sz = mp.size(), j = 0, ans = INF;
24         mp.clear();
25         for ( int i = 0; i < n; i++ )
26         {
27             while ( mp.size() < sz && j < n )
28             {
29                 mp[a[j]]++;
30                 j++;
31             }
32             if ( mp.size() < sz ) break;
33             ans = min( ans, j - i );
34             if ( mp[a[i]] == 1 )
35             {
36                 mp.erase(a[i]);
37             }
38             else
39             {
40                 mp[a[i]]--;
41             }
42         }
43         printf("%d\n", ans);
44     } 
45     return 0;
46 }