hdu 5210 hash统计或stl

方法1：

 1 #include <iostream>
 2 #include <cstring>
 3 using namespace std;
 4
 5 const int N = 101;
 6 int cnt[N];
 7
 8 int main()
 9 {
10     int n, k;
11     while ( cin >> n )
12     {
13         memset( cnt, 0, sizeof(cnt) );
14         for ( int i = 1; i <= n; i++ )
15         {
16             int tmp;
17             cin >> tmp;
18             cnt[tmp]++;
19         }
20         cin >> k;
21         int kinds = 0;
22         for ( int i = 1; i <= n; i++ )
23         {
24             if ( cnt[i] ) kinds++;
25         }
26         int sum = n - kinds;
27         if ( sum < k )
28         {
29             k -= sum;
30             kinds -= k;
31         }
32         cout << kinds << endl;
33     }
34     return 0;
35 }

方法2：

引入set判断重复，代码只有些许改变。

 1 #include <iostream>
 2 #include <set>
 3 using namespace std;
 4
 5 int main()
 6 {
 7     int n, k;
 8     while ( cin >> n )
 9     {
10         set<int> s;
11         for ( int i = 1; i <= n; i++ )
12         {
13             int tmp;
14             cin >> tmp;
15             s.insert(tmp);
16         }
17         cin >> k;
18         int kinds = s.size(), sum = n - kinds;
19         if ( sum < k )
20         {
21             k -= sum;
22             kinds -= k;
23         }
24         cout << kinds << endl;
25     }
26     return 0;
27 }