1 /* 2     DP：从1到最大值，dp[i][1/0] 选或不选，递推更新最大值  3 */  4 #include 
     
       5 #include 
      
        6 #include 
       
         7 #include 
        
          8 using namespace std; 9 10 typedef long long ll;11 const int MAXN = 1e5 + 10;12 const int INF = 0x3f3f3f3f;13 ll dp[MAXN][2];14 ll cnt[MAXN];15 16 ll work(int mx)17 {18     ll ret = 0;19     for (int i=1; i<=mx; ++i)20     {21         dp[i][1] = dp[i-1][0] + cnt[i] * i;22         dp[i][0] = max (dp[i-1][0], dp[i-1][1]);23         ret = max (ret, dp[i][0]);24         ret = max (ret, dp[i][1]);25     }26 27     return ret;28 }29 30 int main(void)      //Codeforces Round #260 (Div. 1) A. Boredom31 {32     int n;    scanf ("%d", &n);33     34     int mx = 0;35     for (int i=1; i<=n; ++i)36     {37         int x;  scanf ("%d", &x);    cnt[x]++;38         mx = max (mx, x);39     }40 41     printf ("%I64d\n", work (mx));42 43     return 0;44 }