贪心 BestCoder Round #39 1001 Delete

题目传送门

 /*
     贪心水题：找出出现次数>1的次数和res，如果要减去的比res小，那么总的不同的数字tot不会少；
             否则再在tot里减去多余的即为答案
     用set容器也可以做，思路一样
 */
 #include <cstdio>
 #include <iostream>
 #include <cstring>
 #include <string>
 #include <algorithm>
 using namespace std;

 const int MAXN = 1e4 + ;
 const int INF = 0x3f3f3f3f;
 int cnt[];

 int main(void)        //BestCoder Round #39 1001 Delete
 {
     //freopen ("1001.in", "r", stdin);

     int n;
     while (scanf ("%d", &n) == )
     {
         int k;
         memset (cnt, , sizeof (cnt));

         int tot = , res = , x;
         for (int i=; i<=n; ++i)
         {
             scanf ("%d", &x);
             if (cnt[x] == )    tot++;
             else if (cnt[x] >= )    res++;
             cnt[x]++;
         }

         scanf ("%d", &k);
         if (res >= k)    printf ("%d\n", tot);
         else    printf ("%d\n", tot - (k - res));
     }

     return ;
 }

 #include <cstdio>
 #include <iostream>
 #include <cstring>
 #include <string>
 #include <algorithm>
 #include <set>
 using namespace std;

 int main(void)        //BestCoder Round #39 1001 Delete
 {
     //freopen ("1001.in", "r", stdin);

     set<int> S;
     int n, k;

     while (cin >> n)
     {
         S.clear ();
         int x;
         for (int i=; i<=n; ++i)
         {
             cin >> x;    S.insert (x);
         }

         cin >> k;
         cout << ((n-S.size () <= k) ? n - k : S.size ()) << endl;
     }

     return ;
 }

使用set容器