参考答案

参考回答：

public class Select {
public static void main(String[] args) {
int[] a = {2,3,3,3,4};
int max = 0;
for(int i=0;i<a.length;i++) {
if(max<a[i])max=a[i];
}
int[] num = new int[max+1];
for(int i=0;i<a.length;i++) {
num[a[i]]++;
}
System.out.println(maxSum(1,max,num));
}
public static int maxSum(int start, int end, int[] num){
int[] sum = new int[end+1];
sum[1] = num[1]*1;
sum[2] = Max(num[1]*1,num[2]*2);
sum[3] = Max((num[1]*1+num[3]*3),num[2]*2);
for(int i=4;i<end+1;i++) {
sum[i] = Max(num[i]*i+sum[i-2],num[i-1]*(i-1)+sum[i-3]);
}
return sum[end];
}
public static int Max(int m, int n){
if(m>n)return m;
else return n;
}
}